Using Other ClojureScript REPLs

While these days most people are using figwheel and shadow-cljs, CIDER supports other ClojureScript REPLs as well. This section of the user manual is dedicated to them.

Node.js REPL

Make sure node.js is installed and that the node binary is on Emacs’s exec-path.

ClojureScript’s Node.js REPL is really simple to setup, as it doesn’t require you to fiddle with your project’s dependencies. All you need to do is:

Open some file in your project.
Type M-x cider-jack-in-cljs RET.
Choose the node option when prompted about the ClojureScript REPL type you want to use.

Weasel

Using Weasel, you can have a browser-connected REPL.

Add [weasel "0.7.1"] to your project’s :dependencies.
Type M-x cider-jack-in-cljs RET and choose the Weasel option when prompted about the ClojureScript REPL type you want to use.

Add this to your ClojureScript code:

(ns my.cljs.core
  (:require [weasel.repl :as repl]))
(repl/connect "ws://localhost:9001")

Once connected you can start evaluating code in the REPL and you’ll see the results in your browser.
```
cljs.user> (js/alert "Hello world!")
```

Provided that a Piggieback-enabled ClojureScript environment is active in your REPL session, code loading and evaluation will work seamlessly regardless of the presence of the cider-nrepl middleware. If the middleware is present then most other features of CIDER will also be enabled (including code completion, documentation lookup, the namespace browser, and macroexpansion).

For more information on Weasel you should consult its documentation.

nbb (node.js babashka)

CIDER has built-in support for nbb. You can either jack in to an nbb project with M-x clojure-jack-in-cljs.

or start its bundled nREPL server:

$ nbb nrepl-server

and connect to it afterwards using M-x cider-connect-cljs.

See the dedicated page for more details.

Other Self-hosted REPLs

For all other self-hosted REPLs you can follow the instructions here. This will work fine with any well-behaved nREPL implementation, like those of: