What are the best languages that compile to JavaScript?

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May 27, 2023

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51 Options Considered

Best languages that compile to JavaScript?	Price	Current stable version	Platforms
87 Elm	-	0.19.1	Windows Linux Mac Web
82 TypeScript	-	3.7	-
81 Nim	-	1.6.12	Windows, MacOS/iOS, Linux /Android/Termux, *BSD, Solaris/SmartOS, HaikuOS, lots of others
79 Kotlin	-	1.3	-
77 Haxe	Free	-	Web, iOS, Android, Blackberry, Windows, OSX, Linux

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score 148 · Answer 1

Elm

Top Pro

No run-time exceptions

Lack of run-time exceptions makes it easy to produce large swathes of reliable front-end code without drowning in tests. See More

Top Con

Lack of typeclasses

Elm doesn't have typeclasses which means some code needs to be duplicated. A fix in a function that needs typeclasses means all of the duplicates need to be fixed too. See More

DeterminedMenoetius's Experience

Tried ClojureScript, PureScript, TypeScript See More

Specs

Current stable version:0.19.1

Platforms:Windows Linux Mac Web

GZipped size:23.2 kB

Top Pro

Inferred static typing

ML static typing is great because it's always there, you just choose how explicit you want to be and how much you want the compiler to do. See More

Top Con

limited js interop

only one way ports are available as a crude js FFI. This means you can only call functions both directions but will not get a result. See More

DeliberateBachue's Experience

I've built 3 large, configurable production apps for various state agencies using Elm integrated with OpenLayers and Turf for Geospatial functionality. See More

Top Pro

Super easy refactoring with very helpful compiler errors

In no other language you can refactor so easy without any worries, since the compiler will guide you through. It is like TDD but than compiler-error driven. See More

Top Con

Harder to get buy-in from devs and mgmt

It's a total divergence from what most people are used to in the JS ecosystem. The change in syntax can be scary, the change in approaching problems can be scary. The fact that it's not backed by FANG can be scary. The fact that it's not v1.0 can be scary. The governance model and the deliberately slow release cadence can be scary. There are a couple harsh medium articles, hackernews/reddit posts out there made by people with an ax to grind that can be scary if you don't have a better picture of the Elm community, the tradeoffs that have been made, or the benefits to be had over other options. None of these are good reasons to write off further investigation of a great tech, but it happens. See More

CromulentNinazu's Experience

Perfect See More

Top Pro

Designed around high-level front-end development

As Elm was designed as a front-end langauge, it has out of the box support for things like DOM-element creation, letting programmers focus on their application logic, rather than implementation details specific to the web. See More

Top Con

Code Repetition

Because of the lack of genericness Elm needs a lot of code to be repeated. There are 130+ implementations of map in elms core libraries. See More

ChattyPeckols's Experience

I have written small programs in Elm. And currently I am building a quite serious PWA in Elm. Writing in Elm is a joy. See More

Top Pro

Great and simple way to learn Purely Functional Programming

You can try to apply some functional programming ideas in other languages that have an imperative basis, but you haven't seen the real power unless you tried it in the environment of purely functional programming. Elm is a simple language with great learning resources and easy graphical output, which makes it easy to explore the power of functional programming. Plus programming in Elm is very readable. See More

Top Con

Features get removed without warning

Often features that are deemed to be misused by the community like infix operators get removed without much of a warning. See More

AdaptableNiamh's Experience

Elm is a nice beginner FP language and get's you a long way. It's the things after that are hard. In recent versions Elm shuts down more and more ways for people to work around limitations (native modules, user-defined operators, local dependencies,..) so every interop tend to be really painful. It's a great start to learn FP and for smaller projects but you have to explore the limitations before commiting. See More

Top Pro

Good tooling

All major editors have great support. With Atom for example, Elm plugins are available for linting, formatting, make/compiler support and Elmjutsu will simply overflow you with super useful functions, like navigate to referenced definition and show expression type. See More

Top Con

Community harsh if criticised

If one even dares to start a discussion about a feature on elms slack, discord, subreddit or github one will be aggressively shut down often argueing that one should use purescript instead See More

AwareNibhaz's Experience

Elm brings back the love for programming See More

Top Pro

Batteries included

The Elm Architecture means you don't need to spend valuable time and effort choosing the right frameworks, state management libraries, or build tooling. It's all built in. See More

Top Con

Poor Windows support

Few if any of Elm's core contributors are Windows users and breaking bugs are sometimes left for weeks or months. See More

GraciousAlalu's Experience

Have used for years in multiple production applications and it worked out very well. Like any tool, it's great for some things and not for others, so make the right choice for your project. Its robustness is perfect for projects that need strong reliability guarantees and the language is simple enough that any competent developer can ramp up on it in a pretty short period of time, so training & hiring are not big issues. I'd recommend it for small to medium size web projects where you want fast development time with really solid reliability and maintainability. It's often not a fit for hackathon projects, projects requiring heavy JS ecosystem integrations, and giant projects (though it can work well for large projects if there's solid team buy-in). See More

Top Pro

Static module system

Elm uses easy to use modules. Use: import List import List as L import List exposing (..) import List exposing ( map, foldl ) import Maybe exposing ( Maybe ) import Maybe exposing ( Maybe(..) ) import Maybe exposing ( Maybe(Just) ) Creation: module MyModule exposing (foo, bar) See More

Top Con

Good for beginners not good for experts

Development in elm is quite nice until you need some more advanced features. These however are actively discontinued and removed because elm wants to establish a "single way of doing things" philosophy See More

CromulentHuixtocihuatl's Experience

Great error messages and feedback loop. See More

Top Pro

Missing syntactic sugar

Easy to learn, most functions have only one way, not 5 alternatives where you must study where to best use what. See More

Top Con

Updates break existing code often

The last few updates of elm broke existing code in major ways. See More

Top Pro

Growing community

Top Con

Adds an additional layer of abstraction

Some users claim that Elm adds an additional layer of abstraction, meaning that it is one more hurdle between the brain and the product. See More

Top Pro

Interactive Programming and Hot Swapping

Support for hot swapping and interactive programming is included. See More

Top Con

Functional programming itself has quite a steep learning curve

Functional programming can be quite difficult to get your head around. It takes time to unlearn object orientational habits. See More

Top Pro

Easy to code review

The lack of side-effects and simple, consistent language semantics make it easy to quickly review incoming changes. See More

Top Con

No Genericness in the future

Currently there is no code genericness like typeclasses possible, it has been officially stated that this will never change. See More

Top Pro

Higher confidence in code correctness and quality

Pure functions, immutable data structures, amazing compiler, clean and homologous syntax used for HTML, logic, and optionally to replace CSS, elimination of entire classes of bugs so you don't even need most unit tests. These factors lead to better code, better programs, higher confidence, and ultimately, more satisfaction. See More

Top Con

Not database-friendly

It is lots of work to make a server or database your "one source of truth", as Elm makes you write endless JSON parse boilerplate to talk to the server. See More

Top Pro

Not quite Haskell semantics

Luckily you do not have to learn Haskell to be able to do any Elm. It is meant to be a language that compiles to Javascript, so for Javascript programmers (Front end) not for CS students who want to learn as many different algorithms as possible. See More

Top Con

No Syntactic Sugar

Often you need to write longer and less readable code because there are no alternatives that are more concise. See More

See All

score 218 · Answer 2

TypeScript

Top Pro

Optional static typing

Typescript has optional static typing with support for interfaces and generics, and intelligent type inference. It makes refactoring large codebases a breeze, and provides many more safeguards for creating stable code. See More

Top Con

Too similar to Javascript

Presents some advantages compared to Javascript, but because it is designed to be a superset of Javascript, it means all the bad parts of Javascript are still present. See More

KlarkC's Experience

I believe TypeScript is the wrong approach to static typing in a functional programming language. It is the jack of all trades and master of none - trying to please all sides. If you are using functional programming, you should pick one: use static typing all the way or nothing. See More

Specs

Current stable version:3.7

IDE Support:Very good

Top Pro

Strong typed language

Lot of benefits of it, you can read this. See More

Top Con

Type checking not enforced by default

You have to use compiler flags to make sure it catches flaws like usage of implicit any, etc. See More

HonestCupid's Experience

Interesting project with some edge still. See More

Top Pro

Strict superset of Javascript

Every existing Javascript program is already a valid TypeScript program giving it the best support for existing libraries, which is particularly useful if you need to integrate with an existing Javascript code base. See More

Top Con

Type inference coverage is incomplete

The default type when declaring and using a variable is any. For example, the following should break but does not: function add(a:number) { return a + 1 } function addAB(a, b) {return add(a) + b} addAB("this should break but doesn't :(", 100) In order to avoid this, you have to declare type signatures for every variable or parameter or set the flag --noImplicityAny when running the compiler. See More

Ɐha Hah's Experience

I got this working with my Vim/Tagbar, so it can't be all that bad. See More

Top Pro

First party Visual Studio support

As a Microsoft developed project, it has first party Visual Studio support that's on par with its C# support with features like syntax sensitive statement completion. See More

Top Con

Requires "this" for field access

Even in cases were there is no ambiguity, you still have to use "this.fieldName" instead of just "fieldName". See More

Top Pro

Has a repository of high quality TypeScript type definitions for popular libraries

There are many ready to use and high quality TypeScript definitions for popular libraries including jquery, angular, bootstrap, d3, lodash and many-many more. See More

Top Con

Syntax is too verbose

Top Pro

Adds support for object-oriented programming

Typescript enables familiar object-oriented programming patterns: classes, inheritance, public/private methods and properties, et cetera. See More

Top Con

No support for dead code elimination

Typescript compiler does not remove dead code from generated file(s), you have to use external tools to remove unused code after compilation. This is harder to achieve, because Typescript compiler eliminated all type information. See More

Top Pro

Polyfill for ES6 fat-arrow syntax

Typescript implements the fat arrow syntax, which always maintains the current context for this and is a shorter/more convenient syntax than traditional function definition. See More

Top Con

No support for conditional compilation

There is no clean way to have debug and release builds compiled from the same source, where the release version removes all debugging tools and outputs from the generated file(s). See More

Top Pro

Great support for React, integrated typed JSX parsing

Strongly typed react components, so UI "templating" automatically gains type safety. See More

Top Con

Awful error messages

Comparing to Elm or Rust for example, TypeScript's error messages won't say you very much. For example if you change method of interface which your class implements it won't say your class have incorrect implementation. Instead it'll show error in usage of instances of class. In some cases it can spoil hours of your work trying to figure out why your parameters are incorrect. See More

Top Pro

Great support for editors (Sublime, Code, Vim, IntelliJ...)

Top Con

Technical debt

As consequence of not enforcing type checking. See More

Top Pro

Works well with existing Javascript code

Both can call Javascript code and be called by Javascript code. Making transitioning to the language very easy. See More

Top Con

Far less typed libraries than Dart (and TSD are never up to date)

Just compare this and this. Typescript => 930 Dart => 2060 See More

Top Pro

Compiles to very native looking code

Compiles to simple looking Javascript making it easy to understand what is happening and learn the language (if you already know Javascript). See More

Top Con

No Java-like package structure

If you prefer a Java-like approach of partitioning your code into different packages, the module system of typescript will confuse you. See More

Top Pro

Built and supported by Microsoft

Being built by Microsoft, TypeScript is much more likely than most other similar open-source projects to receive continued long-term support, good documentation, and a steady stream of development. See More

Top Con

Small community

Top Pro

Ability to do functional programming

Top Con

No option to declare that a function throws errors

Top Pro

Clear roadmap

TypeScript has a clear and defined roadmap with rapid and constant releases. See More

Top Pro

Low number of logical errors brought in by built-in type annotations

TypeScript's built-in type signatures allow developers to fully document interfaces and make sure that they will be correctly compiled. Therefore, cutting down on logical errors. See More

Top Pro

Works well with Angular 2

Angular 2 is built using TypeScript and applications built using it can make use of that (or not). See More

See All

score 39 · Answer 3

Nim

Top Pro

Great metaprogramming features

There are generics, templates, macros in Nim. They can allow you to write new DSL for your application, or avoid all boilerplate stuff. See More

Specs

Current stable version:1.6.12

Platforms:Windows, MacOS/iOS, Linux /Android/Termux, *BSD, Solaris/SmartOS, HaikuOS, lots of others

License:MIT

IDE Support:https://github.com/nim-lang/Nim/wiki/editor-support

See All Specs

Top Pro

Strict typing

Checks your code at compile time. See More

Top Pro

Easy to read

Nim has a lot of common with Python in terms of syntax. Indentation-based syntax, for/while loops. See More

Top Pro

Type interferencing

You only need to specify types in your procedures and objects - you don't need to specify type when you're creating a new variable (unless you're creating it without initialization). See More

Top Pro

Easy to integrate with another languages

You can use Nim with any language that can be interfaced with C. There's a tool which helps you to create new C and C++ bindings for Nim - c2nim. Also, you can use Nim with Objective C or even JavaScript (if you're compiling for these backends). See More

Top Pro

Compile-time execution

Nim has a built-in VM, which executes macros and some other code at compile time. For example, you can check if you're on Windows, and Nim will generate code only for it. See More

Top Pro

Really cross-platform

The same code can be used for web, server, desktop and mobile. See More

Top Pro

Multi paradigm

Imperative, OOP, functional programming in one language. See More

Top Pro

Built-in Unicode support

You can use unicode names for variables, there is "unicode" module for operations with unicode. See More

Top Pro

Garbage-collected

You don't need to deal with all those manual memory allocations, Nim can take care of it. But also you can use another GC, or tweak it for your real-time application or a game. See More

Top Pro

Has built-in unittest module

With built-in "unittest" module you can create test with a very readable code. See More

Top Pro

Supports UFCS (Unified Function Call Syntax)

writeLine(stdout, "hello") can be written as stdout.writeLine("hello") proc add(a: int): int = a + 5 can be used like 6.add.echo or 6.add().echo() See More

Top Pro

Has built-in async support

Nim has "asyncdispatch" module, which allows you to write async applications. See More

See All

score 45 · Answer 4

Kotlin

Top Pro

Amazing IDE support

Since Kotlin is made by Jetbrains (the developers of IntelliJ IDEA) so it stands to reason that the IntelliJ support for Kotlin is also great. See More

Top Con

The need for Java interoperability has forced some limitations

The need to make Kotlin interoperable with Java has caused some unintuitive limitations to the language design. See More

Jake Gage's Experience

Generalized Kotlin does not compile to JavaScript. See More

Specs

Current stable version:1.3

Top Pro

The same language can be used on Frontend and Backend

As Kotlin can be compiled into JS and into JVM it is easy for programmer to develop end-to-end without switching language. See More

Top Con

May be hard for programmers already used to imperative style to learn functional programming from Kotlin

Since Kotlin does not enforce any particular paradigms and is not purely functional, it can be pretty easy to fall back to imperative programming habits if a programmer comes from an imperative background. See More

Top Pro

Java interoperability

Since it runs on the JVM, Kotlin is 100% interoperable with Java and can use existing Java frameworks and libraries. See More

Top Pro

Multi platform support to share business logic

Multi-platform modules allow to share not only data classes and interfaces but also a business logic throughout the whole stack from front end to back end and eventually even native application. See More

Top Pro

Easy to learn if you have prior programming experience

Kotlin's syntax is extremely easy to understand. The language can be picked up in a few hours just by reading the language reference. See More

Top Pro

No runtime overhead

Because the standard library is pretty small and tight, it mostly consists of focused extensions of the Java standard library. See More

Top Pro

Great to share code between Frontend and Backend

API related code (data class, interface) can be compiled into JS, JVM, and native code, so the same code can be used on both sides of communication (front- and backends). This minimizes maintenance overhead and a chance of errors. See More

Top Pro

Fast at runtime

Because Kotlin compiles to the JVM, it can take advantage of the vast amount of work on making the JVM more efficient. Depending on the application the JVM can be almost as efficient as C, and as much as 5-10 times faster than dynamically typed languages like JavaScript or Python. See More

Top Pro

Easy adoption for existing Java programmers

Kotlin runs on the JVM and Java interoperability has been one of the main objectives since the language was born. It runs everywhere Java does; web servers, mobile devices (Android), and desktop applications. It also works with all the major tools in the Java ecosystem like Eclipse, IntelliJ, Maven, Ant, Gradle, Spring Boot, etc. All of this makes adoption extremely easy even for existing Java projects. On top of this there's also ensured Type safety and less boilerplate code needed. See More

Top Pro

Great tooling support

Since Kotlin is made by Jetbrains (the developers of IntelliJ IDEA) so it stands to reason that the IntelliJ support for Kotlin is also great. Besides that, Kotlin also works well with existing Java tools such as Eclipse, Maven, Gradle, Android Studio, etc... See More

Top Pro

Does not impose a particular philosophy of programming

It's not overly OOP like Java and it does not enforce strict functional paradigms either. See More

Top Pro

Is built to solve industrial problems

Kotlin has been designed and built by developers who have an industrial background and not an academic one. As such, it tries to solve issues mostly found in industrial settings. For example, the Kotlin type system helps developers avoid null pointer exceptions. Reasearch languages usually do not have null at all, but APIs and large codebases usually need null. See More

Top Pro

Officially supported for Android development

Starting with version 3.0 of Android Studio, Kotlin support will be built-in. This means that it's now easier than ever to use Kotlin for existing Android projects or even start writing Android apps only with Kotlin from scratch. This also means that Kotlin and Kotlin plugins for Android Studio will be fully supported in the future and their likelihood of being abandoned is quite small since Google is fully embracing the language for their Android ecosystem (alongside Java and C++). See More

Top Pro

Low-risk adoption for existing Java codebases

Since it has such a good interoperability with Java, Java libraries, and Java tools. It can be adopted for an existing Java codebase at little to no cost. The codebase can be converted from Java to Kotlin little by little without ever disrupting the functionality of the application itself. See More

See All

score 192 · Answer 5

Haxe

Top Pro

Compiles to multiple platforms and languages

Haxe allows you to develop for Web, iOS, Android, Blackberry, Windows, OSX, Linux and others, all at once, without the need to switch languages and maintain separate code bases. This is possible because Haxe can compile to JavaScript, ActionScript, Flash AVM bytecode, C++, Neko, PHP, C# (.NET) and Java. Support for even more platforms and languages is under development. See More

Top Con

Bad support in some popular IDEs

While it has great support in Visual Studio Code and Vim for example, it still lacks support in some IDEs such as IntelliJ. See More

UpbeatPunga's Experience

Haxe is an excellent way to use javascript platforms. See More

Specs

Platforms:Web, iOS, Android, Blackberry, Windows, OSX, Linux

Supported languages:C++, C#, Java, Javascript, PHP, Lua, Python, Actionscript

Top Pro

Powerfully expressive but easy to learn

The language was designed to be very expressive with the smallest possible amount of syntactic sugar. There are actually fewer keywords than other languages with similar power. See More

Top Con

You need to code interfaces to work with existing JavaScript code

Some popular libs like JQuery have maintained externs, for any specific code or lib already in JS you have to write the externs to use it in your haxe application. See More

PrincipledSjofn's Experience

Great toolkit See More

Top Pro

Extremely fast compilation

Haxe can easily compile over 100,000 lines of code to JS in seconds on a mid-spec computer. See More

Top Con

No Qt support

There is currently no support for Qt. See More

ElatedMarduk's Experience

One of the best easy-to-use language with wonderful features See More

Top Pro

Similar to JavaScript and ActionScript 3

The language is very easy to learn for those with background in JavaScript or ActionScript 3. See More

Top Con

Full programs only

You can create small utility functions with Haxe, but generally it is a lot more work than with other JS compilers. Haxe is best used when you have a larger project. See More

Top Pro

Large library support. From servers to games.

Haxelib (common library repo) and other sources contain large codebases for anything from cryptography to communications. A lot of these are fully cross platform and work with the JavaScript target. The JavaScript target can be used for everything from node.js server applications (with code completion) to games using either the Flash-like OpenFL library or direct canvas or WebGL programming. See More

Top Con

It's not easy to convince people it's as good as it really is unless you can get them to really try it

Top Pro

Established project

Haxe has been around for more than 10 years (since 2005) and whilst not the most popular project, has had continuous growth. Highly unlikely to disappear or for support to stop. See More

Top Pro

Friendly community

Friendly community See More

Top Pro

Pick up errors at compile time

One big advantage over pure javascript, (or some other languages listed here) is that Haxe will pick up a whole range of errors when you compile, saving you the pain of having to try and debug them later. This includes everything from syntax errors ("Unexpected ;") to type errors ("Class user has no field username. Suggestion: username"). See More

Top Pro

First class code completion

Code completion is built into the compiler and available to the IDE allowing for much smarter code completion that can actually parse and understand the syntax tree. See More

Top Pro

Small, readable output

The output that is generated can be trimmed using "dead code elimination" to only include those functions and libraries that are strictly necessary. All code is very readable with only minimal extras for specific functionality. Small output is good for frontend development as file size is a major concern. See More

Top Pro

Powerful type inference with strong typing

After a type is inferred from its context, it cannot be changed to a new type, and type safety is done at compile time so it stays safe without the extra maintenance required for static typing. See More

Top Pro

Syntactic macros

Syntactic macros allow you to extend compiler features at the syntax tree step. Macros come into play after code is parsed into the abstract syntax tree, and macros allow you to transform it before the rest of the compilation completes. This provides for immense power, while at the same time scoping the extensibility at a level that is powerful, but well constrained. See More

Top Pro

Code reuse server side and client side

You can use the same classes on the server as you do on the client where applicable. This saves a lot of time. See More

Top Pro

Ability to use existing JS libraries

Haxe has the ability to use "externs". These are haxe files which describe the usage of existing JS libraries. Get code completion and compile-time-checking for everything from jQuery to Node.js. Even without externs, native JS code can still be used through untyped code. See More

Top Pro

Can create complex applications without needing webpack, npm or other crutches

Haxe has the power and expression to not need the npm dependancy hell that is common in js and typescript, bit it's still simple. See More

Top Pro

Algebraic data types and pattern matching.

Top Pro

Offload execution to the server with remoting

Using a remoting proxy you can get type safe server to client communications, allowing for remote method execution on the server as if they were part of the client side code. See More

Top Pro

Package management like Java

Package tree is just directory tree, it's wonderful! See More

Top Pro

Builtin conditional compilation support

Haxe supports conditional compilation, so depending on compiler flags Haxe will include or exlcude sections of your code. Making it easy to have debug and release builds. See More

Top Pro

Abstract enums allow constants with exhaustiveness check

You can define constants in an abstract enum and when used in a switch/case statement Haxe checks for exhaustiveness, making sure every constant is covered - with no runtime implication. See More

Top Pro

Type safety for exísting JS libraries

Haxe compiler will check types when using externs for existing libraries. See More

Top Pro

Available in NPM

Top Pro

Ability to skip type checking when calling non Haxe code

You should use externs when calling non Haxe code, but if you just need to call one or two external JS functions, you can skip type checking by calling untyped code. See More

Top Pro

Create without needing to be limited to a language, target, or commercial ecosystem

Top Pro

Abstracts allows me to create more intative api's without runtime overhead

See All

score 76 · Answer 6

ClojureScript

Top Pro

Live interactive programming with figwheel

Figwheel builds your ClojureScript code and hot loads it into the browser as you are coding! Every time you save your ClojureScript source file, the changes are sent to the browser so that you can see the effects of modifying your code in real time. See More

Top Con

Language's functional paradigm is a hurdle for most developers

While the paradigm is part of what should attract users to the language, it's not for the faint of heart. If you've never programmed in a Lisp dialect before, expect to spend a few months becoming proficient in it. See More

SharpCacus's Experience

I've been replacing a large JavaScript application with ClojureScript. Far fewer non-obvious bugs and 1/3 the code in the ClojureScript version. See More

Specs

Current stable version:1.9

GZipped size:32 kB

Top Pro

Active community

ClojureScript has an active and helpful community. There is an active Slack chat and plenty of activity in the Google group. See More

Top Con

Java spin-up time is annoyingly slow

It's simply irritating. See More

Top Pro

Share application logic between browser and Clojure server

Clojure is also able to run web servers, so one can reap similar benefits to NodeJS in terms of sharing code between client and server. See More

Top Con

Syntax may seem cryptic to people not used to Lisp

Lisp is sometimes called "syntax-less" and this is bewildering to those steeped in Algol-type syntax (Java, Javascript, C, etc). Being a dialect of Lisp, ClojureScript's syntax may seem cryptic and hard to understand for people not used to it. While Lisp has very little syntax compared to other languages and it's generally considered pretty terse, there's still an initial overhead in learning the language. See More

Top Pro

Easy to use existing JavaScript libraries

Clojure and ClojureScript are designed to be able to interact with their host. So the language by design makes it is easy to use existing JS libraries. See More

Top Con

The syntax may be hard to learn

Being a dialect of Lisp, ClojureScript's syntax may seem cryptic and hard to understand for people not used to it. While Lisp has very little syntax compared to other languages and it's generally considered pretty terse, there's still an initial overhead in learning the language. But, there's no operator precedence to keep track of, and no mutable local variables that make state hard to keep track of. See More

Top Pro

Targets Google Closure-ready JavaScript for immense optimizations

Google's Closure Compiler converts regular JavaScript into a highly optimized form - including dead code analysis/elimination. It can even remove pieces of unused code from 3rd party libraries (eg, if you import jQuery but only use one function, Google Closure includes only that piece). See More

Top Pro

Immutable data structures out of box

You don't need to think how to save your code immutable. See More

Top Pro

Base language Clojure is very good

Clojure is designed on sound principles. The philosophies of functional programming, immutable data structures, value-oriented programming, and interactive programming all flow through the language to powerful effect. See More

Top Pro

True code re-use

Node.js has promised us code reuse between front-end and back-end which in reality turned out to be a huge myth and mostly lies. Even though you're dealing basically with the same environment (Javascript) on both back-end and front - you still have to write separate code portions targeted specifically for one or another. Turns out with Clojurescript that becomes a reality. Despite the fact that traditionally Clojurescript projects run on JVM in the back-end and in Javascript on the front. See More

Top Pro

Clojure spec

Unfamiliar people very often complain that Clojure is dynamically typed and there's no way to verify correctness of the program. Little they know - there's Clojure Spec. There are not too many type systems out in the wild that are as capable as Spec. Can you easily verify that a function always returns a prime number? In Spec that's trivial. Combined with generative testing Spec gives you an incredible leverage to build robust, solid and predictable programs. See More

Top Pro

Simple syntax

Lispness makes ClojureScript trivial to comprehend after an initial learning overhead See More

Top Pro

Possibility to use well-designed language for browser environment

Top Pro

Excellent tools for web development

ClojureScript has superb wrappers around React.js (see Reagent) that make building single-page apps a breeze. With figwheel, it's a web dev experience unlike any other -- hotloaded code, repl interaction, and instantly reflected changes make good development fun and fast. You can add things like Garden to make CSS-writing part of the same holistic experience and suddenly all development is a pleasant, smooth process. See More

Top Pro

Can be used with React out of the box

Top Pro

Excellent build tools

Both Leiningen and Boot are great build tools that manage code dependencies and deployment. See More

Top Pro

Part of Clojure ecosystem is available for ClojureScript

Top Pro

Allows you to modify JavaScript prototypes

ClojureScript is one of the few programming languages that compile to JavaScript (probably the only one) which allows you to modify JavaScript prototypes without losing compatibility. See More

Top Pro

The Spec core library

From the creator of Clojure: "Spec is a new core library (Clojure 1.9 and Clojurescript) to support data and function specifications in Clojure. Writing a spec should enable automatic: Validation, Error reporting, Destructuring, Instrumentation, Test-data generation and Generative test generation." See More

Top Pro

Live interactive programming with figwheel

Figwheel builds your ClojureScript code and hot loads it into the browser as you are coding! Every time you save your ClojureScript source file, the changes are sent to the browser so that you can see the effects of modifying your code in real time. See More

See All

score 124 · Answer 7

CoffeeScript

Top Pro

Compiles to readable Javascript

With CoffeeScript, there's never really a question of what is going on. If you're worried that something went wrong in the compilation process, the output is very human readable and mostly 1 to 1 with the CoffeeScript code, making debugging easier as the code that is being executed by the interpreter can be double checked. See More

Top Con

Terse syntax can lead to ambiguity

It can sometimes be hard to be sure of what CoffeeScript will compile down to because of the optional parentheses and significant white spacing. Over multiple lines the same statement can be written in many different ways, and it's not always clear what the intended interpretation is. For example: foo bar and hello world can compile to either: foo(bar) && hello(world) foo(bar && hello(world)) See More

PhilosophicalIxchel's Experience

Maintainable code, easy to deal with structures like list. See More

Specs

Current stable version:2.3.2

License:MIT

Top Pro

Widely used

CoffeeScript is the most popular of the compile to Javascript languages, so long term support is much less of a worry than with others. It also means there are many plugins and tools for integrating it into many different build systems, giving it it nearly universal support. See More

Top Con

Initializing a variable and assigning it are essentially the same thing

Because of how variables are initialized and reassigned in CoffeeScript, it becomes very easy to accidentally overwrite a variable as the codebase increases. As complexity increases, the only way to safely create a variable is by pressing Ctrl + F and by examining the current file to ensure that there's no conflict. See More

Ɐha Hah's Experience

Supports Babel 7. See More

Top Pro

Lightweight syntax

Javascript is a very verbose language so CoffeeScript's goal is to lighten it to make it less tedious. Various design choices are built around making CoffeeScript more terse with things like optional parenthesis in function calls, cleaner function declarations, no curly braces, and significant white space. Because Javascript can get pretty deeply nested at times, having a lightweight syntax helps with readability. The result is a language with a minimalistic syntax with lots of syntax sugar. See More

Top Con

Last expression is returned by default

While this is a pro for small functions, it requires self-discipline to check if unnecessary overheads are introduced: eat_full = -> for food in fridge break if full cook food if food.requires_cooking() eat food This will return array of eat function results. Can be fixed by adding empty return at the end. See More

CulturedYucahu's Experience

Now supports Babel 7. See More

Top Pro

It's just JavaScript

The golden rule of CoffeeScript is: "It's just JavaScript". The code compiles one-to-one into the equivalent JS, and there is no interpretation at runtime. You can use any existing JavaScript library seamlessly from CoffeeScript (and vice-versa). The compiled output is readable and pretty-printed, passes through JavaScript Lint without warnings, will work in every JavaScript runtime, and tends to run as fast or faster than the equivalent handwritten JavaScript. See More

Top Pro

Syntax for humans, not compilers.

CoffeeScript adds syntax that is not only more terse than javascript, smoothing over the rough edges, but also enforces a more human readable syntax to the point where a non-programmer can understand some logic. Many programmers that are not use to coffeescripts syntax will find it foreign if they don't read the single page API, but generally it is quick to understand and although self documenting code is a myth coffeescript is definitely very close. if hungry then eat food for food in fridge when food isnt poison and it isnt bedtime Seems a lot more concise and comprehensible to many programmers and most others than the alternative syntax: var food, i, len; if (hungry) { for (i = 0, len = fridge.length; i < len; i++) { food = fridge[i]; if (food !== poison && it !== bedtime) { eat(food); } } } See More

Top Pro

Function syntax is great for callbacks

Passing functions as callbacks is central to how Javascript is written, but the default syntax for functions is very verbose and hard to read. Various CoffeeScript syntax decisions help with ease of writing and reading functions. The most obvious change is that the function keyword is changed from function to ->. Writing out the word function is very clunky especially when you need to use multiple nested functions. One of the more opinionated choices of CoffeeScript is the use of significant whitespace, and optional parens around function arguments. While this can be used poorly, it can also be used to great effect with nested functions. For example, a function that takes an object that defines anonymous functions will end in a mess of parens and curly braces: asyncAction({ success: function(data){ /* handle data */ }, error: function(error){ /* handle errors */ } }); In CoffeeScript you could rewrite this as: asyncAction success: (data) -> /* handle data */ fail: (error) -> /* handle errors */ Other helpful features are automatic returning of the last statement to make short anonymous functions easier so (a, b) -> a+b would replace function (a, b) { return a+b; }, as well as binding functions to the current context object with =>. See More

Top Pro

Splats

Because Javascript functions can take variable amounts of parameters, it is helpful to be able to use splats to extract an array of arguments in a function. For example, if you have a function like: (a, b, rest...) ->any amount of parameters sent to the function after a, b will be stored in an array in the variable rest. You can also put splats at the start or middle of the arguments list, such as (a, middle..., b) ->. When calling a function you can use a splat to apply an array as arguments as well. See More

Top Pro

Everything is an expression

Even for loops and if statements. For example, to get mapped array, you don't have to use any Array methods, just the language features: food = ( stuff for stuff in fridge when stuff.isEatable() ) See More

Top Pro

Familiar to Ruby programmers

CoffeeScript was created by a Ruby programmer and a number of syntax features are modelled on Ruby equivalents, so will be familiar to Ruby programmers. For example, implicit returns, i.e. the last variable of each function is implicitly returned, so "return" keyword need not be present. See More

Top Pro

Extremely easy to document with literate coffeescript

Skip the documentation build, just write documentation with literate CoffeeScript. CoffeeScript has a literate mode which let's you use markdown (used by almost everything, such as reddit, github, stack exchange, etc) with code indented how you would normally in markdown and simply enables you to run the code. This enables you to quickly write FORMATTED, custom documentation that's easily displayed with no build step for the documentation. See More

Top Pro

Source maps allow you to debug code in CoffeeScript

With source maps, you can get the proper location of where an error occurred directly in precompiled code, making it easier to debug without the tedious step of translating the compiled code back to the original code in your head. See More

Top Pro

Significant whitespace

Having indention-based code blocks is particularly helpful in JavaScript because of its functional callback based nature. In JavaScript you find yourself writing functions within object and passing functions to functions. You can find statements ending with a confusing melange of braces like )}})}). With significant whitespace, most of the needs for braces go away. See More

Top Pro

Default choice for Ruby on Rails

Top Pro

Maintainable code

Easy to read and easy to work with structures like list. See More

See All

score 47 · Answer 8

PureScript

Top Pro

Higher kinded types

Has Typeclasses and RankNTypes See More

Top Con

Lots of dependencies needed to get started

Purescript is written in Haskell, but meant to be used with Node.js. As a result, to get started , users must install ghc, cabal, node.js, grunt, and bower. Purescript also has its own compiler, and different semantics form Haskell, and so even after installing, there's still some overhead to getting productive with Purescript. See More

AdaptableNiamh's Experience

easily the best candiate for an functional programming enthusiast. Needs to stabilize it's ecosystem and documentation though - might be hard for beginners without a solid background in another FP language (preferably Haskell I guess) - if you have a background and love FP then go and have a look - you'll not regret it See More

Specs

Current stable version:0.15.4

Top Pro

High performance FFI code

The Eff monad, which is used for FFI code, optimizes out calls to bind, and supports tail call optimization, resulting in clean, efficient Javascript. The psc compiler also specifically recognizes the ST monad, and transforms scoped variables into mutable Javascript variables, for even more efficient code. See More

Top Con

Lack of good IDE/tooling support

Top Pro

Type safety

Compiling should be your first unit test. A tight type system (static and hopefully strong) will catch many logic errors that are often difficult to spot through debugging. In languages like PureScript, if it compiles, it often runs properly. See More

Top Con

Documentation not updated

Top Pro

Pure functional language

You cannot have side effects, unless a function is explicitly defined as so. See More

Top Con

Ecosystem not stable

Top Pro

Modules can be compiled to CommonJS

Modules compiled to CommonJS can be included with 'require', making it incredibly simple to call Purescript code from Javascript. See More

Top Con

Restrictive FFI

Functions exported are all curried, and must be called as such from Javascript. The FFI syntax for importing Javascript functions, while slightly simpler and more readable than UHC/Fay's, means that calls to methods on objects must be wrapped to pass the object explicitly as a parameter. See More

Top Pro

Has row polymorphism and extensible effects

Top Con

Slow compilation

On large project, for example Halogen See More

Top Pro

FFI

FFI system is quite good and easy to use. You can import functions curried or not curried. Records and arrays use native JS objects and arrays. See More

Top Pro

Thorough documentation

The Purescript website has fairly thorough documentation for all of the language's features, and the Purescript blog contains several examples of practical usage. See More

Top Pro

Awesome web frameworks

Thermite (React) Halogen (VDOM, similar to ELM) And hit these up with Signals, Isolated/(Managed?) Components, powerful functions and FFI See More

See All

score 20 · Answer 9

Amber

Top Pro

Includes an IDE

Amber includes an integrated development environment with a class browser, workspace, transcript, object inspector and debugger. See More

Top Con

Very few learning resources

There are very little learning resources for Amber outside the official documentation. Which may not be enough for beginners, especially people that don't have much experience in programming. See More

John Pfersich's Experience

I know Smalltalk so using Amber in some cases is a no- brainer. See More

Specs

Platforms:Windows Linux FreeBSD

Top Pro

Smalltalk is a simple, elegant, and powerful language

Top Pro

One-to-one JS equivalent

Amber is written in itself, including the parser and compiler, and compiles into efficient JavaScript, mapping one-to-one with the JS equivalent. See More

See All

score 67 · Answer 10

Scala.js

Top Pro

Type inference

Scala offers type inference, which, while giving the same safety as Java's type system, allows programmers to focus on the code itself, rather than on updating type annotations. See More

Top Con

Can be intimidating for beginners

Scala is an industrial language. It brings functional programming to the JVM. All books/tutorials cover friendly aspects of Scala, but there are corners of the language that one can wander into that are not friendly to beginners. See More

InterestingAmphitrite's Experience

I find it really robust - I have 20k lines complex scientific code - system dynamic model, it runs in the browser making interactive plots, just works - if tested ok in jvm, no errors in js! See More

Specs

Current stable version:1.13.1

Top Pro

Implements a mature language

In contrast to other options, Scala.js is a compiler plugin for an already existing and mature language: Scala. As such, it benefits automatically from the existing compiler, from the language design choices made for Scala, which exists and is established in the industry since years. See More

Top Con

A complex language with a lot of incidental complexity that results in significant mental overhead

TrustworthyXihe's Experience

Am using scala.js for a complex interactive climate model, it works fast and robustly. See More

Top Pro

Easy, type-safe, interop with JavaScript

The JavaScript-interop of Scala.js is very direct and lightweight. See More

Top Con

Combines OOP and functional programming for a hodge-podge paradigm

Its excellent mix of functional and OOP programming just like Python to use the tool best suited See More

Top Pro

The strength of Scala on the server

The strength of Scala (JVM) on the server can not be underestimated, and is probably superior to any other choice listed here (where applicable; many have no server-side equivalent). Being able to use such a powerful language (and ecosystem) on the server AND on the client, and sharing code between the two, is a big advantage. See More

Top Pro

Extensive standard libraries

Scala.js implements most of the Scala standard library and many parts of the Java one. Among others, it supports Scala's rich collection library. See More

Top Pro

Dead-code elimination

Scala.js performs dead-code elimination out of the box (when running in the "fullOpts" mode). See More

Top Pro

Multiparadigm

Scala supports both Functional and Object Oriented styles of programming. Beginners can learn both paradigms without having to learn a new language, and experts can switch between the two according to what best suits their needs at the time. See More

Top Pro

Crossbuilding

Keeps your client and server sources in sync. See More

Top Pro

Incremental compilation

Through SBT, Scala.js supports incremental compilation out of the box. That is: SBT automatically picks-up the changes (think "watch" in other tools) and only recompiles what is needed. This makes the development cycle fast and very pleasant to work with. See More

Top Pro

Excellent tooling (IDE) support

The same good and mature tooling that can be used for Scala can be used for Scala.js out of the box (code-completion, refactoring, immediate feedback, etc.). See More

Top Pro

Immutable values

The immutable values make it perfect for working with concurrency. See More

Top Pro

Macros

Because Scala.js is a plugin to the Scala compiler, the whole power of the Scala language is available at compile-time. Which includes macros. Very expressive things can be done, in a type-safe way, which are difficult or impossible in other languages. See More

Top Pro

Simple build system compared to Javascript

While SBT is arguably not as simple as Maven, it beats the chaos of the JavaScript build ecosystem. See More

See All

score 10 · Answer 11

PharoJS

Top Pro

Program the web in Smalltalk

For people who enjoy programming in Smalltalk, Pharo allows developers to use Smalltalk for web development as well, since it transpiles Smalltalk code to JavaScript. See More

Top Pro

Support for Phonegap to go directly to iOS/Android mobile App

Top Pro

Compiles to very efficient Javascript, with almost perfect Smalltalk semantics

Top Pro

Great IDE support

Top Pro

Seamless integration with JavaScript libraries

Can directly call to / be called from JavaScript and can use foreign JavaScript objects. Will soon have ability to generate and use AMD modules. See More

See All

score 32 · Answer 12

Babel (6to5)

Top Pro

Support ES6(Harmony)

Babel will turn your ES6+ code into ES5 friendly code, so you can start using it right now without waiting for browser support. See More

Top Con

Generated ES5 is ugly and performs badly

Output looks far from handwritten ES5, is quite large with a lot of extra statements to execute. See More

Specs

Current stable version:7.2.0

IDE Support:Very good

Price:Open Source

Site:http://babeljs.io

Top Pro

Plugins for custom features

Top Con

Compiler is slow compared to other languages

Top Pro

Future forward thinking

See All

score 38 · Answer 13

Reason ML

Top Pro

Uses established compiler technology from Ocaml with a tweaked syntax that leans more towards Javascript

Top Con

A standard async syntax is pending

Async syntax is not standard across native/js projects and in both cases a bit awkward for non-ocaml devs. Currently this is reasonml most voted issue in their GitHub repo so hopefully, there's news soon. See More

Specs

Version:3.6.0

Top Pro

Excellent React support

React Reason comes with builtin reducers based on variants and pattern matching. See More

Top Con

Documentation is sparse

It's still early times for Reason and there's not much documentation or books which makes learning quite difficult. See More

Top Pro

Superior type inference

Ocaml type inference is so smart that you never have to repeat yourself and keep code very clean, type errors also are very pleasant See More

Top Pro

Fast compilation

Compilation is very quick thanks to the OCaml toolchain. See More

Top Pro

A functional language with escape hatches when needed

OOP and mutability are both available if tasks call for them. See More

Top Pro

Native compilation available

Can compile to native binaries (including iOS and Android). See More

Top Pro

REPL available

It's easy and fun to experiment and learn in the rtop REPL. See More

Top Pro

Aims to make the transition from Javascript easier

Despite being a completely different language Javascript programmer will find that the syntax of ReasonML has many familiarities with Javascript. See More

Top Pro

Uses the excellent Bucklescript Ocaml to Javascript transpiler

Top Pro

Immutability with escape hatches

reason includes true immutability, but it has escape hatches to let you use mutations in exceptional cases. See More

Top Pro

JSX syntax natively supoorted

reason was created by the creator of react, for developers already using JSX to template web or native UIs this results very familiar See More

Top Pro

Includes commands to bootstrap projects quickly

The bs-platform package includes the bsb -init command for starting new projects rapidly. See More

Top Pro

Compiles to JavaScript or assembly (ocaml)

The same reasonml code can compile to js (eg. run on browsers or node.js, use any lib in npm), or compile to assembly thru ocaml (unless of course you load js externals), running on any device, with C-comparable (or better) performance. See More

Top Pro

Removes JavaScript "bad parts" but sticks to it's design philosophy

unlike other js-targetting languages that are thought as a way to have a language that pleases community X run in a browser, reason is really designed with JavaScript community in mind. it removes the bad parts but keeps its syntax and its best design principles (from Scheme): simplicity, minimalism, and functions as building block. See More

Top Pro

helpfull and welcome community

The community is very welcoming for newcomers and experienced devs alike. See More

See All

score 16 · Answer 14

F# Fable

Top Pro

Interacts seamlessly with other JavaScript libraries

Specs

Current stable version:2.4.22

License:MIT

IDE Support:Yes

Site:https://fable.io/

See All Specs

Top Pro

Works directly on F# source code, no compilation to .NET bytecode needed

See All

score 168 · Answer 15

Dart

Top Pro

Great async language support

Dart is a single threaded programming language. So if any piece of code blocks the execution of the program, the program practically freezes. To avoid this Dart makes use of asynchronous operations which let your program run without getting blocked. This is done through Future objects. A Future is an object which represent a means for getting a value at a certain point in the future. A function may invoke a Future and when that happens, two outcomes can be achieved: The function is unable to return a value, so it queues up work to be done and returns an uncompleted Future object. Or later when a value is available to be returned, the Future object completes with that value. See More

Top Con

Doesn’t generate consumable JavaScript at present

Dart builds to JavaScript but the entire app needs to be built to JavaScript at once for now (that may change in the future). See More

Specs

Current stable version:2.1.0

IDE Support:Good quality IDE plugins for Jetbrains IDEs and Visual Studio Code

Standard:ECMA

Top Pro

Great standard library

Dart includes a truly comprehensive core library, making it unnecessary to include disparate, external resources for basic functionalities Other than reducing the need to pull in various 3rd-party utilities this also ensures that all Dart code looks and feels the same. Out of the box, the developer gets core libraries to help with: async, collections, strings, regexps, conversions, formats, file I/O, math, typed data, and more. See More

Top Con

Still many holes to fill while converting code to Javascript

While implementing callbacks, passing a type to any function that gets passed to Javascript causes the dart2js compiler to crash. See More

Top Pro

No compile time in development

Dartium (Chromium derivative) is a browser with integrated Dart VM, which allows you to run and debug native Dart code during development for short edit-reload cycles. Only for testing on other browsers and deployment is transpiling to JS necessary. See More

Top Con

Dart SDK does not provide standard (out of the box) way to access SQL-based databases on server side

This missing (but very popular) feature requires to use 3rd-party packages developed by the personal enthusiasts or very small groups of enthusiasts, which is not very convenient because they are all very fragmented in terms of content, the essence and capabilities. See More

Top Pro

A lot of tools are available to help in developing with Dart

Dart has a lot of tools available which help with developing Dart applications. Some examples of those tools include: pub - package and dependency management and build tool analyzer - static syntax analysis with linter, quick fixes, autocompletion support for easy IDE integration test - powerful and flexible testing framework and test runner dev_compiler - generate reusable JS instead of tree-shaken minified JS output (work in progress) dartfmt_ - source code formatter server-side VM observatory - a powerful tool for profiling and debugging running Dart code (for Dartium and Dart server code) See More

Top Con

No strong community involvement in the work on the specification, grammar, language

Dart developers rarely take suggestions on improving the language in consideration. Although the developers have been suggesting changes since 2011 in the mailing list, these suggestions are rarely included in the Dart Enhancement Proposals (DEP) which is mostly written by Google engineers. Some people in the Dart community feel that this is inadequate since a lot of programmers who are part of that community are highly respected engineers and professionals who may have valuable input to give. See More

Top Pro

A very clear well thought standard library

Out of the box, the developer gets core libraries to help with async, collections, strings, regexps, conversions, formats, file I/O, math, typed data, and more. This reduces the need to pull in various 3rd-party utilities and ensures that all Dart code looks and feels the same. See More

Top Con

Small community, little momentum

Top Pro

Transpiled JavaScript code works on all browsers

In Dart many browser differences (subtle differences and also missing features) are abstracted away or polyfilled. When Dart is transpiled to JS the output works on all supported browsers. There is usually no need to load polyfills or to consider browser differences during development. No need for libraries like jQuery to make the same code work the same on all browsers. See More

Top Con

May be difficult to use some JavaScript libraries

Dart is much more than a programming language, it's a platform with its own standard libraries and tools. It's a major departure from JavaScript itself (even though it can compile to JS) that it's not possible to directly interact with JavaScript libraries in Dart. Instead, you have to use a special interop library which exposes the wrapped versions of the JavaScript objects that you are accessing. While this enables Dart to sandbox JavaScript so that its problems do not leak into a Dart application, it also means that it may be cumbersome to use libraries which don't have a wrapper library available. See More

Top Pro

Will be familiar to Java developers

The language will look familiar to Java developers, easing the learning curve. And yet, while it's similar, it has some nice syntax facilities to avoid common boilerplate code found in Java. Code is terser, yet readable. See More

Top Con

Slow development

Many features and tools of the language that were promised a long time ago have yet to be implemented raising concerns that these promises may never be fulfilled. See More

Top Pro

Many platform targets

Dart targets the browser (after it's transpiled to JS), the server (Dart's VM can be run on Linux, Windows, OSX (Both on Intel and ARM architectures), Android and iOS (work in progress) and embedded systems via Dartino (support is experimental). See More

Top Con

Has bad object privacy mechanism with ugly underscores

Library-private members are marked with underscore prefix which is very weird and unreadable syntax. See More

Top Pro

Easy prototyping

Dart has an optional type system which makes Dart a great language for prototyping. It encourages developers to gradually evolve their programs without worrying about types first. See More

Top Pro

Actively developed and maintained

Dart is actively developed and maintained by Google and used by the company, ensuring good project health (even if their plans for the language have changed slightly). See More

Top Pro

Can compile to efficient machine code

Dart was designed to be as expressive as possible. Ahead-of-time compilers can compile Dart code to efficient machine code. This is especially important when deploying to mobile where you don't want (or can't) use a JIT. See More

Top Pro

AngularDart 2.0 support

Top Pro

Optional strong mode.

Strong mode applies a more restrictive type system to Dart to address its unsound, surprising behavior in certain cases. See More

Top Pro

Support of semi-coroutines (generators)

Generators, also known as semicoroutines, are also a generalization of subroutines. Generators are primarily used to simplify the control of iteration behavior of a loop, the yield statement in a generator passes a value back to a parent routine. A generator is very similar to a function that returns an array, in that a generator has a certain number of values. But instead of building and returning an array that contains all the wanted values, a generator returns them one at a time, this saves memory and allows the caller function to start processing the first few values immediately. See More

Top Pro

Upcoming support for cross-platform mobile apps with Flutter

Flutter is a new project to help developers build high-performance, high-fidelity, mobile apps for iOS and Android from a single codebase. See More

Top Pro

The Dart to JavaScript compiler generates high quality source code

Dart to Javascript compiler (dart2js) generates very high quality source code with very high optimization. The output code is also very readable and easy to understand. See More

Top Pro

Supported by major web frameworks, like Angular 2 and Polymer

Dart is one of three natively supported languages for Angular 2, and it has its own Polymer package. See More

Top Pro

Dart is used to build web, server and mobile applications, and for Internet of Things (IoT) devices

Dart, like JavaScript, is a dynamically typed language. It adds optional type annotations to help you catch errors earlier. It takes out a few features of JavaScript, such as prototypes and the global object: this streamlines the VM, enables faster execution, and makes it easier to do code completion and refactoring. And Dart adds some goodies. Dart is more than a new syntax, it’s a full language with its own semantics. When compared to JavaScript, Dart aims to be faster, more regular, and more scalable to large programs. See More

Top Pro

The fastest and performance driven

With using own VM, Dart is the fastest language for the web. Dart is built with performance in mind. It is a nasty decision by microsoft and apple by not embedding Dart VM in their own browsers. Though, compile to js version is also faster than any other Compile to JS languages See More

Top Pro

Supports privacy without verbosity by avoiding the keywords public, protected, and private

Every Dart application is a library, even though it doesn't use a library directive. Libraries not only provide APIs, but are also a unit of privacy. Although in this area Dart is a little bit different from other languages as since is does not have the private, protected or public keywords. Instead Dart uses underscores (_) to denote private functions or variables. For example: foo() is a publicly available function and can be accessed when the library is imported somewhere else. If you want to keep this method hidden, you add an underscore: _foo() and it behaves like protected, now it can't be accessed when the library is imported somewhere else. This helps with having less verbose and easier to understand code See More

Top Pro

Dart to JavaScript compiler designed to create idiomatic, readable JavaScript output

Effective static checking and error detection. A debugging solution for all modern browsers. Readable output. Fast, modular compilation of Dart code. Easy use of generated code from JavaScript. See More

Top Pro

Dart SDK v 2.0 coming soon (at the beginning of 2016 )

New version, new features, better performance, new innovative tools and a lot of other useful and interesting things. See More

Top Pro

Crossplatform

Dart does not just compile to JavaScript, it also compiles to native code on mobile platforms like iOS and Android as demonstrated by flutter.io See More

Top Pro

Runs natively on the server

Dart has its own virtual machine which can be used for developing native Dart code to run on the server without the need to compile it to JavaScript. See More

See All

score 8 · Answer 16

Svelte

Add Video or Image

score 8 · Answer 17

Ruby (via Opal)

Top Pro

Elegant syntax

Ruby has a very clean syntax that makes code easier to both read and write than more traditional Object Oriented languages, such as Java. For beginning programmers, this means the focus is on the meaning of the program, where it should be, rather than trying to figure out the meaning of obscure characters. presidents = ["Ford", "Carter", "Reagan", "Bush1", "Clinton", "Bush2"] for ss in 0...presidents.length print ss, ": ", presidents[presidents.length - ss - 1], "\n"; end See More

Top Con

Meta-programming causes confusion for new developers

The ability for libraries to open classes and augment them leads to confusion for new developers since it is not clear who injected the functionality into some standard class. In other words, if two modules decide to modify the same function on the same class can introduce a number of issues. Mainly, the order in which the modules are included matters. Since you more or less can't tell what kind of "helper" functions a module might write into any class, or for that matter, where the helper function was included from, you may sometimes wonder why class X can do Y sometimes but not at other times. See More

Top Pro

Ceylon

Top Pro

Try it out in the browser

It has a Web IDE: http://try.ceylon-lang.org/ with impressive demos: http://try.ceylon-lang.org/?gist=bd41b47f325b6d32514a so you can try it without installing anything, and see the JS generation / interop in action. See More

Top Con

Lack of physical or electronic books

We should hope Red Hat or anyone interested would take the time and write one. That would strengthen the maturity of the language, but Ceylon is rapidly developing which can make the author's efforts futile because his or hers work will become obsolete soon. The second hindrance is, of course, popularity of the language which can't give much to the pockets of the author (however, Dart's unpopularity at start didn't prevent it to have a lot of printed material, but that's Google's child, we know). See More

Specs

Current stable version:1.3.2

Top Pro

Strong static typing, null safe and flexible, almost dynamic type system

The compiler prevents you from using a potentially null variable, unless you check it is not null. Ie. it forces you to check a potentially null value before using it. The type system is strict, but flexible, allowing union and intersection of types, covariant and contravariant types, reified types, etc. Type inference and union types allows a dynamic programming style, close of JS spirit. See More

Top Con

Currently has large runtime

Ceylon 1.2 needs a language runtime of 1.55 MiB, and the Collection library adds another 370 KiB. That's a lot for the Web... Now, this has to be put in perspective: if you use Ceylon to make a web application, these files will be loaded once, then cached by the browser (that's not casual browsing). Moreover, most servers compress such resource, and the numbers become respectively 234 KiB and 54 KiB, which is more reasonable... See More

Top Pro

Designed from the start to generate JavaScript

It brings type safety to JS, allowing to define interfaces to existing JS APIs, yet using the dynamic keyword for flexible calls in the JS ecosystem. See More

Top Pro

Excellent IDE support

Ceylon has reified generics, so it doesn't loose the type of collections at runtime. This makes autocompletion, debugging, etc. first-class. The Eclipse plugin makes it a full-fledged Ceylon IDE, and an IntelliJ IDEA plugin is in the works. See More

Top Pro

Great tutorial

Gavin King, main author of the language, has a great, clear technical writing style, making understandable difficult concepts like variance or sound type system. See More

Top Pro

Excellent documentation

The language specification is very complete and up to date; also, the language module is very well documented. See More

Top Pro

Javascript interoperability

Ceylon has special language-level support for interoperation with dynamically typed languages like JavaScript, and its module system even interoperates with npm. See More

Top Pro

Easy to learn even if you don't have prior programming experience

Ceylon is indeed fairly easy and readable. Of course those ones who know OOP and a bit of functional programming concepts will feel almost at home right from the start. See More

Top Pro

Generate HTML

HTML generation is supported right in the SDK. See More

Top Pro

Same code in backend and frontend

If you don't use platform-specific features, you can reuse the same code in your backend server (be it in Java or JavaScript) and in your client-side browser code, for example for storing data, validating input etc. See More

See All

score 5 · Answer 19

Haste

Top Pro

Client and Server as the same application

Haste was designed to allow both the client and server to be written as parts of the same, type-safe application. This is in stark contrast to most other options, where the client and server are considered two separate entities, resulting in extra manual validation code and more chances for type errors. See More

Top Con

Lacks some minor Haskell functionality

Lacks support for Template Haskell. See More

Top Pro

Almost full power of Haskell

Haste supports the Haskell 2010 standard except for Template Haskell as well as most GHC extensions. See More

Top Pro

Automatic, type safe program slicing

Haste lets you write client and server as a single program, automatically generating code for the server as well as the client, giving you full type safety even across the Internet. See More

Top Pro

Generates small, reasonably performant code

See All

score 5 · Answer 20

C (via Emscripten)

Top Con

Long learning curve

While the language compliments knowledge of computer components very well, and gives a deeper understanding, it is also quite difficult to learn, and to use correctly, especially without aforementioned knowledge. See More

Top Pro

Incredibly large reservoir of code

C features what may be the largest quantity of libraries and code snippets, from 3D games to web-browsers, from image processing to sound synthesis, file format parsers, data structures, compilers and interpreters. It can even compile and interpret JavaScript code. Practically any algorithm or technology are first implemented in C before being ported to other languages. In some cases, the C library is used directly via FFI, rather than re-implementing the code. Most of the JS standard library in the most commonly used VMs is backed by C implementations. It is rare to find an algorithm that is implemented in some language, and doesn't also have a C implementation. See More

Specs

Current stable version:C'18

Standard:ISO/IEC 9899:2011/Cor 1:2012 or C11

Typing discipline:static

Paradigm:imperative

See All Specs

Top Con

Undefined behaviors and weak limited type safety

Subtle errors can render the entire program "undefined" by the complicated C standard. The standard imposes no requirements in such cases. Thus C compiler is free to ignore the existence of such cases and Bad Things are prone to happen instead. Even experts can't reliably avoid undefined cases in C, so how can beginners be expected to do so? C allows for non-type safe operations such as logic errors, wild pointers, buffer overflow, etc. UB and type safety issues create a large number of bugs and security vulnerabilities. See More

Top Pro

Strict typing

Can perform compile-time assertions and error checking on passed parameters. See More

Top Con

Language is full of corner cases and undefined behaviors

Undefined behavior in a program can cause unexpected results, making it hard to debug. With UB, program behavior may vary wildly depending on optimization settings. There are many cases that invoke UB, such as signed overflow, invalid dereferences, large integer shifts, uninitialized variables, etc. These serve to frustrate novice programmers when they could be learning other concepts. See More

Top Pro

Tried and true

With over 40 years under its belt, C has passed the test of time in a way few other languages have. While other languages as old as C had to go through entire paradigm changes to stay alive, C has only needed a few extra primitive types and operators over the years, to keep up with the capabilities of modern processors. It has actually received less additions than the machine code it usually compiles into, and far less than JavaScript has. Despite this, it is more commonly used, even today. See More

Top Con

Lack of support for first class strings

C does not support the string type, nor does it support UTF-8 strings that modern languages are employing today. Instead of strings, C makes use of the *char type which is a pointer to a character array See More

Top Pro

Extremely high performance

When it comes to performance, there's no competing with native code. Any interpreted language incurs some overhead due to its data model and access patterns. This overhead can be mostly eliminated by using asm.js, which allows the VM to translate all but system calls to efficient undecorated native code. See More

Top Con

Hard to maintain in large projects due to the lack of unit testing

All modern languages worth their salt implements unit testing built into the language so that programmers can implement testing coverage for their entire software project to prevent bugs. However, C does not support unit testing built into the language, which makes the already error-prone language even more error prone. See More

Top Pro

Familiar syntax

Similar to many well known, commonly used programming languages. See More

Top Pro

Easy to drop down to assembly

Sometimes you really need to program directly in assembly. C’s ABI and common compiler extensions make this a piece of cake. See More

Top Pro

Basic concepts can be applied to accelerate learning any other language

You can easily pivot knowledge learned here and apply it to almost every other language. See More

Top Pro

Portable between CPU architectures

C was designed to be independent of any particular machine architecture, and so with a little care, it is easy to write "portable" programs (see here). By design, C provides constructs that map efficiently to typical machine instructions, and therefore it has found lasting use in applications that had formerly been coded in assembly language like operating systems or small embedded systems. See More

Top Pro

C is simple with lesser rules than any other language

C is standardized and it is the go-to language when you have to speed things up. See More

Top Pro

More control over the code

Top Pro

The king of languages, imitated, extended but never equalled

Made of a small set of keywords and rules, only your imagination is the limit. Above all, when it comes to 'pro' programming, C is the only one to rely on. See More

Top Pro

If you can't grok C you should not be a professional programmer

It sets an early bar that if you can't hurdle you might as well do something other than programming and not waste any more of your time. See More

Top Pro

Teaches good practices

Writing in C will require you to understand how things are done. C implies using and understanding the fundamentals. Learning a higher-level language after is much easier. See More

Top Pro

Low level of abstraction

While higher level languages languages like Java and Python provide possibilities to be "more expressive" per line of code, it's much more convenient to start with "less efficient" (get me right) language, in order to get initial concepts of how things behave at lower level. Actually C is a good starting point moving to both higher and lower levels of abstraction, the good example here would be learning C before Assembler, as for general use the Assembler quite hard to understand due to low level of its abstraction (like getting the understanding on how loops work in C before trying to implement them on Assembler). See More

Top Pro

Portable

C is portable between most hardware. Generally a C compiler is made for any new architecture, and already exists for existing architectures. C is portable between all operating systems (Windows, UNIX, Mac, etc.) and only needs a program to be recompiled to work. This allows anyone on any operating system to learn about the language and not be held back by intricacies of their operating system. With this said, C's portability these days is not quite what it used to be. Much of said portability relies on the POSIX standard in particular, and as time passes, the compliance of a given system with that standard is becoming less certain; especially in the case of Linux. Most things will still be portable (or at least emulatable) between Windows, Linux, and FreeBSD for example; but you will at times need to make use of platform-specific support libraries and APIs as well. See More

Top Pro

Must-have

Capability to program in C is greatly appreciated in developers, creates an image of competency, and many programmers will learn it at some point in their careers. See More

Top Pro

Helps with learning other languages later

A lot of languages used in the industry have a C-like syntax (C++, Java, Javascript, C#, PHP) and starting with C will help new developers to be familiar with it's syntax and by extensions with the syntax of many popular languages. See More

Top Pro

Understanding of computers

Learning C forces you to grapple with the low-level workings of your computer (memory management, pointers, etc.) in ways that the other languages abstract away. Without an understanding of these low-level aspects of computer programming you will be limited if you try to develop an application that needs to run in a memory or performance constrained environment. Other languages like Python can obscure a lot of details, so your foundation may be weaker. See More

Top Pro

Industry standard

C is the industry standard programming language, moreover, it is the most popular programming language to use. C is the language used for most Windows, UNIX and Mac operating systems. See More

See All

What are the best languages that compile to JavaScript?

51 Options Considered

Elm

My Recommendation for Elm

My Recommendation for Elm

No run-time exceptions

Lack of typeclasses

Inferred static typing

limited js interop

Super easy refactoring with very helpful compiler errors

Harder to get buy-in from devs and mgmt

Designed around high-level front-end development

Code Repetition

Great and simple way to learn Purely Functional Programming

Features get removed without warning

Good tooling

Community harsh if criticised

Batteries included

Poor Windows support

Static module system

Good for beginners not good for experts

Missing syntactic sugar

Updates break existing code often

Growing community

Adds an additional layer of abstraction

Interactive Programming and Hot Swapping

Functional programming itself has quite a steep learning curve

Easy to code review

No Genericness in the future

Higher confidence in code correctness and quality

Not database-friendly

Not quite Haskell semantics

No Syntactic Sugar

TypeScript

My Recommendation for TypeScript

My Recommendation for TypeScript

Optional static typing

Too similar to Javascript

Strong typed language

Type checking not enforced by default

Strict superset of Javascript

Type inference coverage is incomplete

First party Visual Studio support

Requires "this" for field access

Has a repository of high quality TypeScript type definitions for popular libraries

Syntax is too verbose

Adds support for object-oriented programming

No support for dead code elimination

Polyfill for ES6 fat-arrow syntax

No support for conditional compilation

Great support for React, integrated typed JSX parsing

Awful error messages

Great support for editors (Sublime, Code, Vim, IntelliJ...)

Technical debt

Works well with existing Javascript code

Far less typed libraries than Dart (and TSD are never up to date)

Compiles to very native looking code

No Java-like package structure

Built and supported by Microsoft

Small community

Ability to do functional programming

No option to declare that a function throws errors

Clear roadmap

Low number of logical errors brought in by built-in type annotations

Works well with Angular 2

Nim

My Recommendation for Nim

My Recommendation for Nim

Great metaprogramming features

Strict typing

Easy to read

Type interferencing

Easy to integrate with another languages

Compile-time execution

Really cross-platform

Multi paradigm

Built-in Unicode support

Garbage-collected

Has built-in unittest module

Supports UFCS (Unified Function Call Syntax)