Refactor and convert JS codebase to ESM

.github/workflows/ci.yml

@@ -45,6 +45,11 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: .nvmrc
+
       - name: Restore build cache
         id: build-cache
         uses: actions/cache@v4
@@ -401,11 +406,11 @@ jobs:
         run: |
           opam exec -- node packages/playground-bundling/scripts/generate_cmijs.js
           opam exec -- dune build --profile browser
-          cp ./_build/default/compiler/jsoo/jsoo_playground_main.bc.js playground/compiler.js
+          cp ./_build/default/compiler/jsoo/jsoo_playground_main.bc.js playground/compiler.cjs
 
       - name: Test playground compiler
         if: matrix.build_playground
-        run: node playground/playground_test.js
+        run: node playground/playground_test.cjs
 
       - name: Upload playground compiler to CDN
         if: ${{ matrix.build_playground && startsWith(github.ref, 'refs/tags/v') }}

.github/workflows/get_artifact_dir_name.js

@@ -1,10 +1,10 @@
-const fs = require("fs");
-const os = require("os");
+import * as fs from "node:fs";
+import * as os from "node:os";
 
-const { dirName: artifactDirName } = require("../../cli/bin_path.js");
+import { platformName } from "#cli/bins";
 
 // Pass artifactDirName to subsequent GitHub actions
 fs.appendFileSync(
   process.env.GITHUB_ENV,
-  `artifact_dir_name=${artifactDirName}${os.EOL}`,
+  `artifact_dir_name=${platformName}${os.EOL}`,
 );

.github/workflows/prepare_package_upload.js

@@ -1,7 +1,8 @@
-const fs = require("fs");
-const os = require("os");
+import * as fs from "node:fs";
+import * as os from "node:os";
+
+import packageSpec from "rescript/package.json" with { type: "json" };
 
-const packageSpec = require("rescript/package.json");
 const { version } = packageSpec;
 
 const commitHash = process.argv[2] || process.env.GITHUB_SHA;

.gitignore

@@ -72,7 +72,7 @@ playground/stdlib/
 playground/*.cmj
 playground/*.cmi
 playground/.netrc
-playground/compiler.js
+playground/compiler.*js
 
 rewatch/target/
 rewatch/rewatch
@@ -88,3 +88,5 @@ tests/analysis_tests/**/*.bs.js
 !.yarn/releases
 !.yarn/sdks
 !.yarn/versions
+
+*.tsbuildinfo

CHANGELOG.md

@@ -19,6 +19,7 @@
 #### :house: Internal
 
 - Remove `Stdlib_Char` module for now. https://github.com/rescript-lang/rescript/pull/7367
+- Convert internal JavaScript codebase into ESM, ReScript package itself is now ESM (`"type": "module"`). https://github.com/rescript-lang/rescript/pull/6899
 
 # 12.0.0-alpha.10
 

CONTRIBUTING.md

@@ -263,7 +263,7 @@ $ node
 
 ### Testing the Playground bundle
 
-Run `node playground/playground_test.js` for a quick sanity check to see if all the build artifacts are working together correctly. When releasing the playground bundle, the test will always be executed before publishing to catch regressions.
+Run `node playground/playground_test.cjs` for a quick sanity check to see if all the build artifacts are working together correctly. When releasing the playground bundle, the test will always be executed before publishing to catch regressions.
 
 ### Working on the Playground JS API
 
@@ -273,7 +273,7 @@ Whenever you are modifying any files in the ReScript compiler, or in the `jsoo_p
 make playground
 
 # optionally run your test / arbitrary node script to verify your changes
-node playground/playground_test.js
+node playground/playground_test.cjs
 ```
 
 ### Publishing the Playground Bundle on our KeyCDN

Makefile

@@ -61,7 +61,7 @@ artifacts: lib
 # Builds the core playground bundle (without the relevant cmijs files for the runtime)
 playground:
 	dune build --profile browser
-	cp ./_build/default/compiler/jsoo/jsoo_playground_main.bc.js playground/compiler.js
+	cp ./_build/default/compiler/jsoo/jsoo_playground_main.bc.js playground/compiler.cjs
 
 # Creates all the relevant core and third party cmij files to side-load together with the playground bundle
 playground-cmijs: artifacts
@@ -70,7 +70,7 @@ playground-cmijs: artifacts
 # Builds the playground, runs some e2e tests and releases the playground to the
 # CDN (requires KEYCDN_USER and KEYCDN_PASSWORD set in the env variables)
 playground-release: playground playground-cmijs
-	node playground/playground_test.js
+	node playground/playground_test.cjs
 	sh playground/upload_bundle.sh
 
 format:
@@ -86,7 +86,7 @@ clean-rewatch:
 	cargo clean --manifest-path rewatch/Cargo.toml && rm -f rewatch/rewatch
 
 clean:
-	(cd runtime && ../cli/rescript clean)
+	(cd runtime && ../cli/rescript.js clean)
 	dune clean
 
 clean-all: clean clean-gentype clean-rewatch 

analysis/examples/example-project/types.json

@@ -8,6 +8,6 @@
     }
   ],
   "custom": [
-    {"module": "Belt_HashMapInt", "path": [], "name": "t", "args": 1}
+    { "module": "Belt_HashMapInt", "path": [], "name": "t", "args": 1 }
   ]
-}
+}

biome.json

@@ -1,16 +1,34 @@
 {
-  "$schema": "https://biomejs.dev/schemas/1.8.3/schema.json",
+  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
   "vcs": {
     "enabled": true,
     "clientKind": "git",
     "defaultBranch": "master",
     "useIgnoreFile": true
   },
   "linter": {
-    "enabled": false
+    "enabled": true,
+    "rules": {
+      "recommended": true,
+      "style": {
+        "useTemplate": "off"
+      },
+      "nursery": {
+        "noCommonJs": "error"
+      },
+      "suspicious": {
+        "noAssignInExpressions": "warn"
+      },
+      "correctness": {
+        "useImportExtensions": "error",
+        "noUndeclaredDependencies": "error",
+        "noUnusedImports": "error",
+        "noUnusedVariables": "warn"
+      }
+    }
   },
   "organizeImports": {
-    "enabled": false
+    "enabled": true
   },
   "formatter": {
     "enabled": true,
@@ -19,24 +37,7 @@
     "indentWidth": 2,
     "lineEnding": "lf",
     "lineWidth": 80,
-    "attributePosition": "auto",
-    "ignore": [
-      ".yarn/**",
-      "tests/build_tests/**",
-      "tests/tests/**",
-      "tests/tools_tests/**",
-      "tests/analysis_tests/**",
-      "tests/docstring_tests/**",
-      "analysis/examples/**",
-      "analysis/reanalyze/examples/**",
-      "lib/**",
-      "ninja/**",
-      "playground/**",
-      "**/*.bs.js",
-      "**/*.res.js",
-      "**/*.gen.ts*",
-      "package.json"
-    ]
+    "attributePosition": "auto"
   },
   "javascript": {
     "formatter": {
@@ -50,5 +51,27 @@
       "quoteStyle": "double",
       "attributePosition": "auto"
     }
+  },
+  "files": {
+    "ignore": [
+      ".yarn/**",
+      "tests/analysis_tests/**/src/**",
+      "tests/build_tests/**/src/**",
+      "tests/docstring_tests/**",
+      "tests/gentype_tests/**",
+      "tests/tests/**/src/**",
+      "tests/tools_tests/**/src/**",
+      "analysis/examples/**/src/**",
+      "lib/es6/**",
+      "lib/js/**",
+      "ninja/**",
+      "packages/**",
+      "playground/**",
+      "*.bs.js",
+      "*.res.js",
+      "*.res.mjs",
+      "*.gen.ts*",
+      "package.json"
+    ]
   }
 }

cli/bsc.js

@@ -0,0 +1,18 @@
+#!/usr/bin/env node
+
+// @ts-check
+
+import { execFileSync } from "node:child_process";
+
+import { bsc_exe } from "./common/bins.js";
+
+const delegate_args = process.argv.slice(2);
+
+try {
+  execFileSync(bsc_exe, delegate_args, { stdio: "inherit" });
+} catch (e) {
+  if (e.code === "ENOENT") {
+    console.error(String(e));
+  }
+  process.exit(2);
+}