Run eslint on .mjs files. NFC (#21563)

Author: sbc100

.eslintrc.yml

@@ -1,11 +1,12 @@
 env:
   browser: true
-  es2020: true
+  es2022: true
   node: true
 extends:
   - prettier
 parserOptions:
   ecmaVersion: 13
+  sourceType: "module"
 ignorePatterns:
   - "out/"
   - "site/"
@@ -54,7 +55,10 @@ rules:
   max-len: "off"
   no-multi-spaces: "off"
   require-jsdoc: "off"
-  no-unused-vars: "off"
   arrow-body-style: ["error", "as-needed"]
   space-infix-ops: "error"
   quotes: ["error", "single", {"avoidEscape": true}]
+overrides:
+  - files: "**/*.mjs"
+    rules:
+      no-unused-vars: ["error", {"vars": "all", "args": "none", "ignoreRestSiblings": false, "destructuredArrayIgnorePattern": "^_" }]

package.json

@@ -19,7 +19,7 @@
     "html-minifier-terser": "7.2.0"
   },
   "scripts": {
-    "lint": "eslint .",
+    "lint": "eslint --ext .js --ext .mjs .",
     "fmt": "prettier --write src/*.mjs tools/*.mjs",
     "check": "prettier --check src/*.mjs tools/*.mjs"
   }

test/test_browser.py

@@ -3363,8 +3363,12 @@ def test_async_mainloop(self, args):
     self.btest_exit('async_mainloop.cpp', args=args + ['-sASYNCIFY'])
 
   @requires_sound_hardware
-  def test_sdl_audio_beep_sleep(self):
-    self.btest_exit('test_sdl_audio_beep_sleep.cpp', args=['-Os', '-sASSERTIONS', '-sDISABLE_EXCEPTION_CATCHING=0', '-profiling', '-sSAFE_HEAP', '-lSDL', '-sASYNCIFY'], timeout=90)
+  @parameterized({
+    '': ([],),
+    'safeheap': (['-sSAFE_HEAP'],),
+  })
+  def test_sdl_audio_beep_sleep(self, args):
+    self.btest_exit('test_sdl_audio_beep_sleep.cpp', args=['-Os', '-sASSERTIONS', '-sDISABLE_EXCEPTION_CATCHING=0', '-profiling', '-lSDL', '-sASYNCIFY'] + args, timeout=90)
 
   def test_mainloop_reschedule(self):
     self.btest('mainloop_reschedule.cpp', '1', args=['-Os', '-sASYNCIFY'])

tools/acorn-optimizer.mjs

@@ -10,10 +10,6 @@ function print(x) {
   process.stdout.write(x + '\n');
 }
 
-function printErr(x) {
-  process.stderr.write(x + '\n');
-}
-
 function read(x) {
   return fs.readFileSync(x).toString();
 }
@@ -33,13 +29,6 @@ function assertAt(condition, node, message = '') {
   }
 }
 
-function warnOnce(msg) {
-  if (!warnOnce.msgs) warnOnce.msgs = {};
-  if (msg in warnOnce.msgs) return;
-  warnOnce.msgs[msg] = true;
-  printErr('warning: ' + msg);
-}
-
 // Visits and walks
 // (We don't use acorn-walk because it ignores x in 'x = y'.)
 
@@ -100,12 +89,6 @@ function emptyOut(node) {
   node.type = 'EmptyStatement';
 }
 
-function nullify(node) {
-  node.type = 'Literal';
-  node.value = null;
-  node.raw = 'null';
-}
-
 // This converts the node into something that terser will ignore in a var
 // declaration, that is, it is a way to get rid of initial values.
 function convertToNothingInVarInit(node) {
@@ -114,11 +97,6 @@ function convertToNothingInVarInit(node) {
   node.raw = 'undefined';
 }
 
-function convertToNull(node) {
-  node.type = 'Identifier';
-  node.name = 'null';
-}
-
 function convertToNullStatement(node) {
   node.type = 'ExpressionStatement';
   node.expression = {
@@ -304,13 +282,6 @@ function runJSDCE(ast, aggressive) {
   function iteration() {
     let removed = 0;
     const scopes = [{}]; // begin with empty toplevel scope
-    function DUMP() {
-      printErr('vvvvvvvvvvvvvv');
-      for (let i = 0; i < scopes.length; i++) {
-        printErr(i + ' : ' + JSON.stringify(scopes[i]));
-      }
-      printErr('^^^^^^^^^^^^^^');
-    }
     function ensureData(scope, name) {
       if (Object.prototype.hasOwnProperty.call(scope, name)) return scope[name];
       scope[name] = {
@@ -549,7 +520,6 @@ function applyImportAndExportNameChanges(ast) {
         }
       });
     } else if (node.type === 'AssignmentExpression') {
-      const target = node.left;
       const value = node.right;
       if (isExportUse(value)) {
         const name = value.property.value;
@@ -737,7 +707,6 @@ function emitDCEGraph(ast) {
       emptyOut(node); // ignore this in the second pass; this does not root
     } else if (node.type === 'AssignmentExpression') {
       const target = node.left;
-      const value = node.right;
       // Ignore assignment to the wasmExports object (as happens in
       // applySignatureConversions).
       if (isExportUse(target)) {
@@ -902,7 +871,7 @@ function emitDCEGraph(ast) {
       info.reaches[nameToGraphName[import_]] = 1;
     } // otherwise, it's a number, ignore
   }
-  for (const [e, name] of Object.entries(exportNameToGraphName)) {
+  for (const [e, _] of Object.entries(exportNameToGraphName)) {
     const name = exportNameToGraphName[e];
     infos[name] = {
       name: name,
@@ -1127,7 +1096,7 @@ function littleEndianHeap(ast) {
         // replace the heap access with LE_HEAP_STORE
         const name = target.object.name;
         const idx = target.property;
-        switch (target.object.name) {
+        switch (name) {
           case 'HEAP8':
           case 'HEAPU8': {
             // no action required - storing only 1 byte

tools/preprocessor.mjs

@@ -17,7 +17,6 @@ import assert from 'assert';
 import {loadSettingsFile} from '../src/utility.mjs';
 
 const args = process.argv.slice(2);
-const debug = false;
 
 assert(args.length >= 2, 'Script requires 2 arguments');
 const settingsFile = args[0];

tools/unsafe_optimizations.mjs

@@ -32,12 +32,6 @@ function visitNodes(root, types, func) {
   }
 }
 
-function dump(nodeArray) {
-  for (const node of nodeArray) {
-    console.dir(node);
-  }
-}
-
 function optPassSimplifyModularizeFunction(ast) {
   visitNodes(ast, ['FunctionExpression'], (node) => {
     if (node.params.length == 1 && node.params[0].name == 'Module') {