cljs-npm-deps-mjs-issue

This repo provides a simple way to reproduce a bug in ClojureScript that causes JS projects that use .mjs extensions for ES6 modules to not be detected correctly.

Steps to reproduce

Run the following command to build out/main.js:

clj -Sdeps '{:deps {org.clojure/clojurescript {:mvn/version "1.10.64"}}}' \
    -i build.clj

Open index.html in the browser (e.g. open index.html)
- Open the browser devtools
- Refresh the page

Expected result

The devtools JS console logs the iterall module.

Actual result

The devtools JS console logs the following error:

base.js:1357 Uncaught Error: Undefined nameToPath for iterall
    at visitNode (base.js:1357)
    at Object.goog.writeScripts_ (base.js:1369)
    at Object.goog.require (base.js:706)
    at index.html:7

Observations

out/cljs_deps.js

This file should contain goog.addDependency entries for the iterall package. Instead, all it contains is this:

goog.addDependency("base.js", ['goog'], []);
goog.addDependency("../cljs/core.js", ['cljs.core'], ['goog.string', 'goog.Uri', 'goog.object', 'goog.math.Integer', 'goog.string.StringBuffer', 'goog.array', 'goog.math.Long']);
goog.addDependency("../process/env.js", ['process.env'], ['cljs.core']);
goog.addDependency("../foo/core.js", ['foo.core'], ['cljs.core', 'iterall']);

Given this, it's no surprise that main.js fails to resolve iterall.

Node module indexing

The following command prints the output of ClojureScript's Node module indexing (thanks @swannodette) and greps for iterall:

clj -Sdeps '{:deps {org.clojure/clojurescript {:mvn/version "1.10.64"}}}' \
    -e "(require '[cljs.closure :as cc] '[clojure.pprint :refer [pprint]]) (pprint (cc/index-node-modules-dir))" \
  | grep -C3 iterall

The output is:

  :module-type :es6,
  :provides ["tapable/lib/Tapable.js" "tapable/lib/Tapable" "tapable"]}
 {:file
  "/Users/jannis/Work/oss/jannis/cljs-npm-deps-mjs-issue/node_modules/iterall/index.js",
  :module-type :es6,
--
  :module-type :es6,
  :provides ["iterall/index.js" "iterall/index" "iterall"]}
 {:file
--
 {:file
  "/Users/jannis/Work/oss/jannis/cljs-npm-deps-mjs-issue/node_modules/iterall/package.json",
  :module-type :es6}

The first match is interesting: node_modules/iterall/index.js does not exist. What exists instead os node_modules/iterall/index.mjs.

Jannis / cljs-npm-deps-mjs-issue