JavaScript vs C

JavaScript looks for every possible way to treat the code you write as runnable and is very reluctant to point out likely errors. For example, you have call a function with too many arguments, the extra arguments are simply discarded.

If you forget a var or new, you can clobber the global scope. For tiny scripts (JavaScript's original use case) globals are great, but for larger applications globals are generally regarded as a Bad Thing. This is because changes to one small part of a program can randomly break things anywhere else. These kinds of bugs are notoriously hard to find.

Since JavaScript is a weakly typed language, you don't have to learn about data types if you start using JavaScript as your first language. Data types being one of the most important concepts in programming. This will also cause trouble in the long run when you will have to (inevitably) learn and work with a strongly or statically typed language because you will be forced to learn the type system from scratch.

'5' - 1 == 4, but '5' + 1 == 51. There are other examples that make even less sense.

JavaScript has a long litany of warts and gotchas. JavaScript will bite you if you're just a wee bit careless. You have to exercise a great deal of caution and awareness. You either have to know the entire 545-page ES6 spec to avoid them all, or use a linter to help restrict you from using the bad parts (and you still have to be familiar with the language), but beginners don't know these things. (Linters are also prone to time-wasting false positives.) This is a significant cognitive burden on even the experienced programmer (as if coding wasn’t hard enough already), but try learning to program in the first place on top of all of this and you'll understand that JavaScript is a terrible choice for the beginner.

It wouldn't consolidate a good mind structure for moving to other languages. Too open.

Beginner programmers often make the mistake of coding something, seeing it works in the browser they tested it in, and then scratching their heads when it doesn't work in another browser. Ideally you'd want a language that works consistently across all platforms in order to be able to focus more on the programming and less on the underlying environment. It just takes time away from learning and forces you to spend time figuring out why this worked in browser X but not browser Y.

Trying to keep up=javascript fatigue. You won't have time to learn anything else if this is your first language, and you will probably think all programmers are crazy. Plus web assembly may open the door for better alternatives.

this is bound to whatever object called the function. Unless you invoke it as a method. Unless you invoke it as a constructor. Unless it's an arrow function.

Much often needed functionality is not in the standard library. (Contrast with Python.) However, there are well established libraries such as Lodash, to fill the gap (however, due to the diverse/fractured ecosystem it may not be clear what library to use).

JavaScript can work synchronously but its current use is mainly around asynchronous instructions, and it's surely not a good way to start learning programming.

Therefore, attempts to call methods on them will fail. This is especially frustrating since these are often returned instead of throwing exceptions. So a failure may appear far away from the actual cause, which makes bugs very hard to find.

Many cases when you should get an Array, you just get an Array-like object instead and none of the Array methods work on it.

The language and the web platform move fast these days. this makes it difficult for students as there is a lot of fragmentation and outdated information.

This is very surprising for beginners. Especially since 00 through 07 seem to work just fine. And this isn't just for hardcoded numbers. The parseInt() function has the same problem, but only on some systems.

You really want to be using a good editor (light IDE) and a linter, type checker (e.g.:Flow), etc. until you grok the language. And choosing / setting-up that development environment is it's own learning curve. If taught in a classroom, using a subset of JS with solid tools, there is an argument that JS could be an ideal first language... however, that is a lot of ceremony to protect the new programmer from JS gotchas. But without the tools, JS can be a very painful painful first language (trying to figure out why your code isn't doing what you intended).

JS is one of the most dreaded languages as it was designed for the purpose of becoming just an scripting language for a browser. It was never intended to take over as the leading technology in web development, thus the language has been streched past its own capabilities. A beginer should learn something else first, something that is better conceived and refined.

JavaScript is rather inconsistent when dealing with different types. For example, when working with the + operator and two numbers, they will be added, two strings will be concatenated:

3+5; // 8;
"Hello "+"world"; // "Hello world"

When using + with a string and a non-string operand, the non-string operand is converted to a string and the result is concatenated:

"the answer is "+42; // "the answer is 42"
"this is "+true; // "this is true"

In any other case (except for Date) the operands are converted to numbers and the results are added:

1+true; // = 1+1 = 2; 
null+false; // = 0+0 = 0;

Angular, React, Ember, Meteor, Backbone, Knockout, Express, Mithril, Aurelia. The web frameworks pass in and out of fashion too quickly to keep up with. The endless civil wars are becoming tiresome.

But beginners won't know better. And even after you learn, you might have to deal with others' code that uses the bad stuff. JavaScript was originally developed in 10 days. It just wasn't designed that carefully.

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.

Learning programming is already hard enough when you don't have to worry about memory leaks.

The C standard library is not type safe, and the language itself does not promote type safety built into the language, which leads to error-proneness of the language. If anything, it would be recommended that those interested in C to instead put their time in D, which actually includes a complete copy of the C standard library rewritten to be fully type safe.

While other programmers will learn algorithms and structures and will do magic tricks and awesome applications, you will learn trash info that you should know maybe after 5-7 years experience in software development, not earlier. It's like going the first time as a seven year old kid to first school class, and your teacher tells you to learn you about Discrete Math, without basic math and how to do 2x2.

If you wish to be a really good programmer, C for sure will be in your portfolio, but not as a first language, and this programming language is used only for very hard and very limited tools which require a lot of professional skills from the programmer.

Header files are a poor man's implementation of modules. Modern programming languages make use of modules which eliminate the need for C includes and header files and the many issues caused by them, such as the complete lack of dependency checking. Header files often contain even more include statements that point to other header files which also point to even more which drastically increases compile time. Modules only have to be compiled once, and when importing those modules into your software project, you only have to pull in the module that you are using, which is often times already precompiled. This way, the compiler knows exactly what it needs before beginning to compile your project and can automatically compile the few dependencies it needs in advance rather than recursively compiling every header file it runs across as in C.

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.

Depending on the purpose this can be either a pro or a con. If the task is to learn how to program, low-level of C will impend learning important concepts. Furthermore, C is rather limited in ways of building abstractions.

"Low-levelness" of C can be a pro feature in learning system programming.

There are languages like Rust, Object Pascal, D, Golang, Vlang, Odin, Zig, Jai, etc... that can be used instead. The other languages are easier to understand, use, and/or about as fast.

In the same manner that C recursively compiles header files ad infinitum without any sort of dependency checking, C source code is also compiled in the same manner. If you attempt to call a function before it is declared, the compiler will fail because the function was not compiled before it was caled.

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.

When an array is passed to a function, it is converted to a pointer, even though the prototype confusingly says it's an array. When this conversion happens, all array type information gets lost. C arrays also cannot not be resized, which means that even simple aggregates like a stack are complicated to implement. C arrays also cannot be bounds checked, because they don't know what the array bounds are.

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.

Older languages, like C, are no longer in their hay day. Even if you do learn it as your first language, you are only setting yourself up to need to learn another language in the long run. If you want a skill that you can not only learn from, but also potentially build a career on, C should not be your first choice.

The C programming language is not portable to other operating systems, and even different compilers, because the C language does not provide any reference cross platform libraries or compilers. Different platforms and compilers provide their own implementation of the C standard library which may not be compatible with the implementation in another compiler or platform. Without cross platform libraries and tools, one cannot state that C is portable. This is in stark contrast to modern programming languages that provide their own cross platform libraries and compilers, such as D, Go and Rust.

Modern programming languages are capable of compiling split source code files by concatenating them together efficiently at compile time before compiling them. However, C requires the developer to resort to messing with header files and makefiles to get similar functionality.

C structs lack a lot of modern capabilities that are vital in programming languages of today, such as assigning member functions to structs to give them object-oriented capabilities, constructs, deconstructors and RAII. Great care must be used when using structs in C to prevent memory leaks and ridiculously slow structs.

All the modern languages have resulted in ditching the ancient deprecated model of #include statements and have instead adopted the superior model of modules. When compiling software written in C, the programmer is forced to also compile X headers which contain Y headers which contain Z headers and so forth -- drastically increasing the number of lines that need to be compiled. In order to compile something as simple as "Hello, World", for example, 18K lines of code needs to be compiled. This can be very taxing on RAM and CPU resources, causing compile times to quickly absorb a large portion of the programming process.

C lacks a large majority of programming concepts that modern languages make use of today. The existing functionality of C makes use of outdated and deprecated methodologies which can be of great annoyance to the modern day programmer.