Racket vs ClojureScript

Realm of Racket teaches the big-bang approach for managing world state. It does so by walking the reader through the development of small games. There are few guidebooks that are as useful and entertaining.

Racket is based on Scheme (LISP Family) and is very similar to Clojure. So there are a ton of (). The reason it is easier to learn is that it is not trying to be "Pure" if there is even such a thing in terms of Functional Programming. The great thing about Racket is it has everything included. You get DrRacket for developing programs. You want to add a picture to your software you can insert pictures. If you want to add libraries just open the package manager. The Syntax is an opinion but it really does feel easier to see what is happening since everything is in brackets)
Racket is a really a Programming Language for making Programming Languages. So there are smaller syntax Racket called Student Racket which makes things easier to pick up.

Includes several free online books and great documentation.

Racket has an active community of users/developers that makes it easy to get help when needed.

Although syntax is different from that of mainstream languages, S-expressions are a perfect match to functional programming.

Racket makes it inconvenient to pursue imperative habits while encouraging functional programming by Lisps's syntax. For example, the syntax for defining a function is almost the exact same as defining a variable. In addition, Racket has a strong set of higher-order functions built in to the language.

Racket is famously embedded in the game engine underlying Naughty Dog's Uncharted and The Last of Us games, because it proved to be so easy to embed.

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.

Lispness makes ClojureScript trivial to comprehend after an initial learning overhead.

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.

Google's Closure Library 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).

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.

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

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.

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.