nrepl-cljs-sci

nREPL server for NodeJS using SCI.

Usage

nrepl-cljs-sci can be used both in plain JS projects and in CLJS projects. See example/js for JS project example and example/cljs.

The start_server (start-server in CLJS) function takes an argument, that can be a JS object or a Clojure map. You can pass a reference to application state under the app key, which is the available at the nrepl repl under js/app symbol.

For example, use from JS project:

$ cd example/js
$ node index.js
Example app listening at http://localhost:3000
2021-08-01T18:48:35.553Z INFO [nrepl-cljs-sci.core:206] - nRepl server started on port 59600. nrepl-cljs-sci version 0.0.10

Then, in another shell:

$ curl http://localhost:3000
Hello World!

Connect to the nRepl server and run the following:

user> js/app
#js {:express_app #object[app], :root #js {:response "Hello World!"}}
user> (set! (.-response js/app.root) "Hello SCI!")
nil

Now, check the result via curl:

$ curl http://localhost:3000
Hello SCI!

Development instructions

1. Start shadow-cljs server (for faster compile invocations)

bb shadow-server

2. Compile nrepl-cljs-sci to JavaScript

bb shadow-compile

3. Run nrepl-cljs-sci

bb node-server

4. Run nrepl client

bb nrepl-client
nREPL server started on port 54784 on host localhost - nrepl://localhost:54784
[Rebel readline] Type :repl/help for online help info

5. Send nrepl requests to the server

user=> (require '[nrepl.core :as nrepl])
nil
user=> (with-open [conn (nrepl/connect :port 7788)]
  #_=>   (let [response (nrepl/message (nrepl/client conn 1000) {:op "describe"})]
  #_=>     (println response)))
({:aux {}, :id af22bc8e-164a-4d22-b67d-6c676f1262a0, :ops {:describe {}, :eval {}}, :status [done], :versions {:nghttp2 1.41.0, :napi 7, :modules 83, :brotli 1.0.9, :zlib 1.2.11, :tz 2020a, :v8 8.4.371.19-node.18, :node 14.16.0, :openssl 1.1.1j, :icu 67.1, :cldr 37.0, :ares 1.16.1, :llhttp 2.1.3, :unicode 13.0, :uv 1.40.0}})
nil
user=> (with-open [conn (nrepl/connect :port 7788)]
  #_=>   (let [response (nrepl/message (nrepl/client conn 1000) {:op "eval" :code "(+ 1 1)"})]
  #_=>     (println response)))
({:id d4c78721-61de-4b20-a428-2fa941d49eb1, :ns user, :status [done], :value 2})
;; JS interop works too
user=> (with-open [conn (nrepl/connect :port 7788)]
  #_=>   (let [response (nrepl/message (nrepl/client conn 1000) {:op "eval" :code "js/process.versions"})]
  #_=>     (println response)))
({:id 0360a3a9-7899-417b-a195-ff999e0d2486, :ns user, :status [done], :value {:nghttp2 1.41.0, :napi 7, :modules 83, :brotli 1.0.9, :zlib 1.2.11, :tz 2020a, :v8 8.4.371.19-node.18, :node 14.16.0, :openssl 1.1.1j, :icu 67.1, :cldr 37.0, :ares 1.16.1, :llhttp 2.1.3, :unicode 13.0, :uv 1.40.0}})

Changelog

See CHANGELOG.md