[JS] Adopt additional modern JS patterns and ESLint rules. NFC

eslint.config.mjs

@@ -79,6 +79,11 @@ export default [{
     'arrow-body-style': ['error', 'as-needed'],
     'space-infix-ops': 'error',
     'prefer-object-has-own': 'error',
+    'prefer-exponentiation-operator': 'error',
+    'prefer-object-spread': 'error',
+    'prefer-rest-params': 'error',
+    'prefer-spread': 'error',
+    'logical-assignment-operators': ['error', 'always'],
 
     quotes: ['error', 'single', {
       avoidEscape: true,

src/deterministic.js

@@ -6,7 +6,7 @@
 
 let MAGIC = 0;
 Math.random = () => {
-  MAGIC = Math.pow(MAGIC + 1.8912, 3) % 1;
+  MAGIC = ((MAGIC + 1.8912) ** 3) % 1;
   return MAGIC;
 };
 

src/jsifier.mjs

@@ -641,7 +641,7 @@ export async function runJSify(outputFile, symbolsOnly) {
         }
         return `\
 function(${args}) {
-  dbg("[library call:${mangled}: " + Array.prototype.slice.call(arguments).map(prettyPrint) + "]");
+  dbg("[library call:${mangled}: " + Array.from(arguments, prettyPrint) + "]");
   ${run_func}
   dbg("  [     return:" + prettyPrint(ret));
   return ret;
@@ -1023,7 +1023,7 @@ function(${args}) {
         //  emits
         //   'var foo;[code here verbatim];'
         contentText = 'var ' + mangled + snippet;
-        if (snippet[snippet.length - 1] != ';' && snippet[snippet.length - 1] != '}') {
+        if (snippet.at(-1) != ';' && snippet.at(-1) != '}') {
           contentText += ';';
         }
       } else if (typeof snippet === 'undefined') {

src/lib/libbrowser.js

@@ -285,7 +285,7 @@ var LibraryBrowser = {
 
 #if MIN_SAFARI_VERSION < 160400
       var CFS = document.exitFullscreen ?? document['webkitCancelFullScreen'];
-      CFS.apply(document, []);
+      CFS.call(document);
 #else
       document.exitFullscreen();
 #endif

src/lib/libcore.js

@@ -2525,7 +2525,7 @@ function wrapSyscallFunction(x, library, isWasi) {
       post += 'SYSCALLS.varargs = undefined;\n';
     }
   }
-  pre += `dbg('syscall! ${x}: [' + Array.prototype.slice.call(arguments) + ']');\n`;
+  pre += `dbg('syscall! ${x}: [' + Array.from(arguments) + ']');\n`;
   pre += 'var canWarn = true;\n';
   pre += 'var ret = (() => {';
   post += '})();\n';

src/lib/libdylink.js

@@ -537,7 +537,7 @@ var LibraryDylink = {
     }
 
 #if ASSERTIONS
-    var tableAlign = Math.pow(2, customSection.tableAlign);
+    var tableAlign = 2 ** customSection.tableAlign;
     assert(tableAlign === 1, `invalid tableAlign ${tableAlign}`);
     assert(offset == end);
 #endif
@@ -554,9 +554,7 @@ var LibraryDylink = {
     for (var [sym, exp] of Object.entries(exports)) {
       if (sym.startsWith('dynCall_')) {
         var sig = sym.substring(8);
-        if (!hasOwn(dynCalls, sig)) {
-          dynCalls[sig] = exp;
-        }
+        dynCalls[sig] ??= exp;
       }
     }
   },
@@ -719,7 +717,7 @@ var LibraryDylink = {
     if (firstLoad) {
 #endif
       // alignments are powers of 2
-      var memAlign = Math.pow(2, metadata.memoryAlign);
+      var memAlign = 2 ** metadata.memoryAlign;
       // prepare memory
       var memoryBase = metadata.memorySize ? alignMemory(getMemory(metadata.memorySize + memAlign), memAlign) : 0; // TODO: add to cleanups
       var tableBase = metadata.tableSize ? {{{ from64Expr('wasmTable.length') }}} : 0;

src/lib/libembind.js

@@ -60,7 +60,7 @@ var LibraryEmbind = {
       // Inject an overload resolver function that routes to the appropriate overload based on the number of arguments.
       proto[methodName] = function(...args) {
         // TODO This check can be removed in -O3 level "unsafe" optimizations.
-        if (!hasOwn(proto[methodName].overloadTable, args.length)) {
+        if (!proto[methodName].overloadTable[args.length]) {
           throwBindingError(`Function '${humanName}' called with an invalid number of arguments (${args.length}) - expects one of (${proto[methodName].overloadTable})!`);
         }
         return proto[methodName].overloadTable[args.length].apply(this, args);
@@ -91,7 +91,7 @@ var LibraryEmbind = {
       // We are exposing a function with the same name as an existing function. Create an overload table and a function selector
       // that routes between the two.
       ensureOverloadTable(Module, name, name);
-      if (hasOwn(Module[name].overloadTable, numArguments)) {
+      if (Module[name].overloadTable[numArguments]) {
         throwBindingError(`Cannot register multiple overloads of a function with the same number of arguments (${numArguments})!`);
       }
       // Add the new function into the overload table.
@@ -144,7 +144,7 @@ var LibraryEmbind = {
 
   $registerInheritedInstance: (class_, ptr, instance) => {
     ptr = getBasestPointer(class_, ptr);
-    if (hasOwn(registeredInstances, ptr)) {
+    if (registeredInstances[ptr]) {
         throwBindingError(`Tried to register registered instance: ${ptr}`);
     } else {
         registeredInstances[ptr] = instance;
@@ -153,7 +153,7 @@ var LibraryEmbind = {
 
   $unregisterInheritedInstance: (class_, ptr) => {
     ptr = getBasestPointer(class_, ptr);
-    if (hasOwn(registeredInstances, ptr)) {
+    if (registeredInstances[ptr]) {
         delete registeredInstances[ptr];
     } else {
         throwBindingError(`Tried to unregister unregistered instance: ${ptr}`);
@@ -1972,10 +1972,8 @@ Originally allocated`); // `.stack` will add "at ..." after this sentence
 
         if (classType.registeredClass.__derivedClasses) {
           for (const derivedClass of classType.registeredClass.__derivedClasses) {
-            if (!hasOwn(derivedClass.constructor, methodName)) {
-              // TODO: Add support for overloads
-              derivedClass.constructor[methodName] = func;
-            }
+            // TODO: Add support for overloads
+            derivedClass.constructor[methodName] ??= func;
           }
         }
 

src/lib/libembind_shared.js

@@ -39,7 +39,7 @@ var LibraryEmbindShared = {
     if (!rawType) {
       throwBindingError(`type "${name}" must have a positive integer typeid pointer`);
     }
-    if (hasOwn(registeredTypes, rawType)) {
+    if (registeredTypes[rawType]) {
       if (options.ignoreDuplicateRegistrations) {
         return;
       } else {
@@ -50,7 +50,7 @@ var LibraryEmbindShared = {
     registeredTypes[rawType] = registeredInstance;
     delete typeDependencies[rawType];
 
-    if (hasOwn(awaitingDependencies, rawType)) {
+    if (awaitingDependencies[rawType]) {
       var callbacks = awaitingDependencies[rawType];
       delete awaitingDependencies[rawType];
       callbacks.forEach((cb) => cb());
@@ -74,14 +74,11 @@ var LibraryEmbindShared = {
     var unregisteredTypes = [];
     var registered = 0;
     for (let [i, dt] of dependentTypes.entries()) {
-      if (hasOwn(registeredTypes, dt)) {
+      if (registeredTypes[dt]) {
         typeConverters[i] = registeredTypes[dt];
       } else {
         unregisteredTypes.push(dt);
-        if (!hasOwn(awaitingDependencies, dt)) {
-          awaitingDependencies[dt] = [];
-        }
-        awaitingDependencies[dt].push(() => {
+        (awaitingDependencies[dt] ??= []).push(() => {
           typeConverters[i] = registeredTypes[dt];
           ++registered;
           if (registered === unregisteredTypes.length) {

src/lib/libemval.js

@@ -307,7 +307,7 @@ ${functionBody}
       var rv;
       switch (kind) {
         case {{{ cDefs['internal::EM_INVOKER_KIND::FUNCTION'] }}}:
-          rv = Emval.toValue(handle).apply(null, argN);
+          rv = Emval.toValue(handle)(...argN);
           break;
         case {{{ cDefs['internal::EM_INVOKER_KIND::CONSTRUCTOR'] }}}:
           rv = Reflect.construct(Emval.toValue(handle), argN);

src/lib/libglemu.js

@@ -3542,7 +3542,7 @@ var LibraryGLEmulation = {
     GLImmediate.matricesModified = true;
     GLImmediate.matrixVersion[GLImmediate.currentMatrix] = (GLImmediate.matrixVersion[GLImmediate.currentMatrix] + 1)|0;
     GLImmediate.matrixStack[GLImmediate.currentMatrix].push(
-        Array.prototype.slice.call(GLImmediate.matrix[GLImmediate.currentMatrix]));
+        GLImmediate.matrix[GLImmediate.currentMatrix].slice());
   },
 
   glPopMatrix: () => {
@@ -3570,7 +3570,7 @@ var LibraryGLEmulation = {
 
   glLoadMatrixf: (matrix) => {
 #if GL_DEBUG
-    if (GL.debug) dbg('glLoadMatrixf receiving: ' + Array.prototype.slice.call(HEAPF32.subarray(matrix >> 2, (matrix >> 2) + 16)));
+    if (GL.debug) dbg('glLoadMatrixf receiving: ' + HEAPF32.subarray(matrix >> 2, (matrix >> 2) + 16));
 #endif
     GLImmediate.matricesModified = true;
     GLImmediate.matrixVersion[GLImmediate.currentMatrix] = (GLImmediate.matrixVersion[GLImmediate.currentMatrix] + 1)|0;

src/lib/libglfw.js

@@ -884,28 +884,28 @@ var LibraryGLFW = {
       } 
 
       if (DataTransferItem.prototype.webkitGetAsEntry) {
-        let entriesTree = {};
+        let entriesTree = new Map();
         function markDone(fullpath, recursive) {
-          if (entriesTree[fullpath].subpaths.length != 0) return;
-          delete entriesTree[fullpath];
+          if (entriesTree.get(fullpath).subpaths.length != 0) return;
+          entriesTree.delete(fullpath);
           let parentpath = fullpath.substring(0, fullpath.lastIndexOf('/'));
-          if (!hasOwn(entriesTree, parentpath)) {
-            if (Object.keys(entriesTree).length == 0) finalize();
+          if (!entriesTree.has(parentpath)) {
+            if (entriesTree.size == 0) finalize();
             return;
           }
-          const fpIndex = entriesTree[parentpath].subpaths.indexOf(fullpath);
-          if (fpIndex > -1) entriesTree[parentpath].subpaths.splice(fpIndex, 1);
+          const fpIndex = entriesTree.get(parentpath).subpaths.indexOf(fullpath);
+          if (fpIndex > -1) entriesTree.get(parentpath).subpaths.splice(fpIndex, 1);
           if (recursive) markDone(parentpath, true);
-          if (Object.keys(entriesTree).length == 0) finalize();
+          if (entriesTree.size == 0) finalize();
         }
         function processEntry(entry) {
           let fp = entry.fullPath;
           let pp = fp.substring(0, fp.lastIndexOf('/'));
-          entriesTree[fp] = { subpaths: [] };
+          entriesTree.set(fp, { subpaths: [] });
           if (entry.isFile) {
             entry.file((f) => { filesQ.push({ file: f, path: pp }); markDone(fp, false); })
           } else if (entry.isDirectory) {
-            if (hasOwn(entriesTree, pp)) entriesTree[pp].subpaths.push(fp);
+            if (entriesTree.has(pp)) entriesTree.get(pp).subpaths.push(fp);
             FS.createPath('/' + drop_dir + pp, entry.name);
             var reader = entry.createReader();
             var rRead = function (dirEntries) {

src/lib/liblegacy.js

@@ -106,15 +106,7 @@ legacyFuncs = {
 #if EMBIND
   $getInheritedInstanceCount: () => Object.keys(registeredInstances).length,
 
-  $getLiveInheritedInstances: () => {
-    var rv = [];
-    for (var k in registeredInstances) {
-      if (hasOwn(registeredInstances, k)) {
-        rv.push(registeredInstances[k]);
-      }
-    }
-    return rv;
-  },
+  $getLiveInheritedInstances: () => Object.values(registeredInstances),
 #endif
 };
 

src/lib/libmemfs.js

@@ -333,7 +333,7 @@ addToLibrary({
               if (contents.subarray) {
                 contents = contents.subarray(position, position + length);
               } else {
-                contents = Array.prototype.slice.call(contents, position, position + length);
+                contents = contents.slice(position, position + length);
               }
             }
             HEAP8.set(contents, ptr);

src/lib/libsdl.js

@@ -1914,7 +1914,7 @@ var LibrarySDL = {
     var srcData = SDL.surfaces[src];
     var w = srcData.width * zoom;
     var h = srcData.height * zoom;
-    var diagonal = Math.ceil(Math.sqrt(Math.pow(w, 2) + Math.pow(h, 2)));
+    var diagonal = Math.ceil(Math.hypot(w, h));
     var ret = SDL.makeSurface(diagonal, diagonal, srcData.flags, false, 'rotozoomSurface');
     var dstData = SDL.surfaces[ret];
     dstData.ctx.translate(diagonal / 2, diagonal / 2);
@@ -3354,10 +3354,7 @@ var LibrarySDL = {
     var gamepad = SDL.getGamepad(deviceIndex);
     if (gamepad) {
       var name = gamepad.id;
-      if (hasOwn(SDL.joystickNamePool, name)) {
-        return SDL.joystickNamePool[name];
-      }
-      return SDL.joystickNamePool[name] = stringToNewUTF8(name);
+      return SDL.joystickNamePool[name] ??= stringToNewUTF8(name);
     }
     return 0;
   },

src/lib/libwasmfs_fetch.js

@@ -22,7 +22,7 @@ addToLibrary({
       var url = '';
       var fileUrl_p = __wasmfs_fetch_get_file_url(file);
       var fileUrl = UTF8ToString(fileUrl_p);
-      var isAbs = fileUrl.indexOf('://') !== -1;
+      var isAbs = fileUrl.includes('://');
       if (isAbs) {
         url = fileUrl;
       } else {

src/lib/libwebgl.js

@@ -3149,7 +3149,7 @@ for (let i = 0; i <= GL_POOL_TEMP_BUFFERS_SIZE; ++i) {
 #if GL_TRACK_ERRORS
       var bindingsType = 0x8872/*GL_MAX_TEXTURE_IMAGE_UNITS*/;
 #endif
-      if (bindingMatch[3] && bindingMatch[2].indexOf('sampler') != -1) {
+      if (bindingMatch[3] && bindingMatch[2].includes('sampler')) {
         samplerBindings[bindingMatch[3]] = [binding, arrayLength];
       } else {
 #if GL_TRACK_ERRORS

src/parseTools.mjs

@@ -120,7 +120,7 @@ export function preprocess(filename) {
   let inStyle = false;
   const lines = text.split('\n');
   // text.split yields an extra empty element at the end if text itself ends with a newline.
-  if (!lines[lines.length - 1]) {
+  if (!lines.at(-1)) {
     lines.pop();
   }
 

src/postamble_minimal.js

@@ -328,7 +328,7 @@ null;
 #endif
     // WebAssembly compilation failed, try running the JS fallback instead.
     var search = location.search;
-    if (search.indexOf('_rwasm=0') < 0) {
+    if (!search.includes('_rwasm=0')) {
       location.href += (search ? search + '&' : '?') + '_rwasm=0';
     }
 #if ENVIRONMENT_MAY_BE_NODE || ENVIRONMENT_MAY_BE_SHELL

src/preamble.js

@@ -555,7 +555,7 @@ async function instantiateArrayBuffer(binaryFile, imports) {
 #endif
       // WebAssembly compilation failed, try running the JS fallback instead.
       var search = location.search;
-      if (search.indexOf('_rwasm=0') < 0) {
+      if (!search.includes('_rwasm=0')) {
         // Reload the page with the `_rwasm=0` argument
         location.href += (search ? search + '&' : '?') + '_rwasm=0';
         // Return a promise that never resolves.  We don't want to

src/runtime_debug.js

@@ -275,8 +275,8 @@ function prettyPrint(arg) {
   if (arg.toString() == '[object HTMLImageElement]') {
     return arg + '\n\n';
   }
-  if (arg.byteLength) {
-    return '{' + Array.prototype.slice.call(arg, 0, Math.min(arg.length, 400)) + '}';
+  if (arg.subarray) {
+    return '{' + arg.subarray(0, 400) + '}';
   }
   if (typeof arg === 'function') {
     return '<function>';

src/utility.mjs

@@ -58,7 +58,7 @@ export function popCurrentFile() {
 
 function errorPrefix(lineNo) {
   if (!currentFile.length) return '';
-  const filename = currentFile[currentFile.length - 1];
+  const filename = currentFile.at(-1);
   if (lineNo) {
     return `${filename}:${lineNo}: `;
   } else {
@@ -313,7 +313,7 @@ class Profiler {
 
   terminate() {
     while (this.ids.length) {
-      const lastID = this.ids[this.ids.length - 1][0];
+      const lastID = this.ids.at(-1)[0];
       this.stop(lastID);
     }
     // const overall = performance.now() - this.startTime

test/codesize/test_codesize_cxx_ctors1.json

@@ -1,10 +1,10 @@
 {
-  "a.out.js": 19093,
-  "a.out.js.gz": 8090,
+  "a.out.js": 19070,
+  "a.out.js.gz": 8074,
   "a.out.nodebug.wasm": 133990,
   "a.out.nodebug.wasm.gz": 51234,
-  "total": 153083,
-  "total_gz": 59324,
+  "total": 153060,
+  "total_gz": 59308,
   "sent": [
     "__cxa_throw",
     "_abort_js",

test/codesize/test_codesize_cxx_ctors2.json

@@ -1,10 +1,10 @@
 {
-  "a.out.js": 19070,
-  "a.out.js.gz": 8074,
+  "a.out.js": 19047,
+  "a.out.js.gz": 8058,
   "a.out.nodebug.wasm": 133418,
   "a.out.nodebug.wasm.gz": 50931,
-  "total": 152488,
-  "total_gz": 59005,
+  "total": 152465,
+  "total_gz": 58989,
   "sent": [
     "__cxa_throw",
     "_abort_js",