actually cant detect collection polyfills

connorjclark · connorjclark · commit 59a45617fc41 · 2025-03-05T12:53:18.000-08:00
diff --git a/cli/test/smokehouse/test-definitions/legacy-javascript.js b/cli/test/smokehouse/test-definitions/legacy-javascript.js
@@ -31,7 +31,7 @@ const expectations = {
           items: [
             {
               url: 'http://localhost:10200/legacy-javascript.js',
-              wastedBytes: '134000 +/- 2000',
+              wastedBytes: '127000 +/- 2000',
               subItems: {
                 items: [
                   {signal: 'Object.getOwnPropertyDescriptor'},
@@ -115,7 +115,6 @@ const expectations = {
                   {signal: 'String.prototype.trimEnd'},
                   {signal: 'String.prototype.trimStart'},
                   {signal: 'String.prototype.trim'},
-                  {signal: 'WeakSet'},
                   {signal: 'Promise.any'},
                   {signal: 'String.prototype.replaceAll'},
                   {signal: '@babel/plugin-transform-classes'},
diff --git a/core/audits/byte-efficiency/legacy-javascript.js b/core/audits/byte-efficiency/legacy-javascript.js
@@ -181,8 +181,10 @@ class LegacyJavascript extends ByteEfficiencyAudit {
       // {target:"Array",proto:true,forced:!HAS_SPECIES_SUPPORT||!USES_TO_LENGTH},{filter:
       expression += `|{target:${qt(objectWithoutPrototype)}\\S*},{${property}:`;
     } else {
-      // WeakSet, etc.
-      expression += `|function ${property}\\(`;
+      // Map, Set, WeakSet, etc.
+      // collection("Map",
+      // Currently not used. See create-polyfill-module-data.js
+      // expression += `|collection\\(${qt(property)},`;
     }
 
     return expression;
diff --git a/core/audits/byte-efficiency/polyfill-graph-data.json b/core/audits/byte-efficiency/polyfill-graph-data.json
@@ -1,97 +1,96 @@
 {
-  "moduleSizes": [26070, 498, 282, 294, 281, 467, 161, 227, 236, 229, 765, 546, 339, 1608, 723, 729, 1545, 438, 214, 657, 111, 759, 537, 209, 281, 685, 217, 757, 3015, 3401, 631, 293, 182, 475, 79, 407, 140, 366, 792, 191, 269, 222, 158, 280, 188, 137, 158, 105, 189, 543, 160, 742, 1436, 88, 904, 146, 314, 375, 183, 1083, 195, 503, 269, 208, 334, 350, 460, 568, 229, 1155, 334, 266, 30, 120, 309, 370, 480, 358, 1952, 1638, 304, 153, 274, 1288, 192, 543, 74, 144, 137, 33, 336, 457, 2122, 535, 711, 1323, 117, 1961, 244, 557, 318, 119, 124, 108, 144, 96, 133, 441, 210, 1627, 1956, 693, 1426, 863, 637, 301, 51, 708, 583, 119, 600, 221, 370, 728, 1085, 552, 629, 125, 1746, 97, 441, 543, 2756, 371, 447, 548, 243, 266, 217, 99, 440, 183, 546, 137, 464, 207, 983, 171, 992, 503, 237, 382, 249, 675, 402, 254, 223, 164, 214, 191, 831, 218, 202, 232, 124, 249, 160, 251, 217, 717, 78, 561, 1627, 256, 386, 225, 432, 499, 394, 364, 445, 634, 667, 177, 346, 470, 663, 142, 588, 414, 617, 1559, 380, 2520, 1040, 417, 289, 238, 220, 214, 303, 163, 141, 510, 397, 137, 137, 133, 133, 390, 266, 137, 183, 215, 191, 485, 328, 575, 799, 533, 148, 215, 589, 589, 130, 362, 562, 471, 179, 186, 1266, 1456, 521, 1536, 427, 444, 406, 912, 150, 283, 144, 485, 470, 1787, 205, 1268, 796, 658, 306, 3751, 321, 331, 814, 146, 2328, 1226, 922, 237, 206, 198, 250, 283, 261, 58, 46, 59, 53, 52, 60, 49, 54, 56, 3000],
+  "moduleSizes": [26070, 498, 282, 294, 281, 467, 161, 236, 229, 765, 546, 339, 1608, 723, 729, 1545, 438, 214, 657, 111, 759, 537, 209, 281, 685, 217, 757, 631, 293, 182, 475, 79, 407, 140, 366, 792, 269, 222, 158, 280, 188, 137, 158, 105, 189, 543, 160, 742, 1436, 88, 904, 146, 314, 375, 183, 1083, 195, 503, 269, 208, 334, 350, 460, 568, 229, 1155, 334, 266, 30, 120, 309, 370, 358, 1952, 1638, 304, 153, 274, 1288, 192, 543, 74, 144, 137, 33, 336, 457, 2122, 535, 711, 1323, 117, 1961, 244, 557, 318, 119, 124, 108, 144, 96, 133, 441, 210, 1627, 1956, 693, 1426, 863, 637, 301, 51, 708, 583, 119, 600, 221, 370, 728, 1085, 552, 629, 125, 1746, 97, 441, 543, 2756, 371, 447, 548, 243, 266, 217, 99, 440, 183, 546, 137, 464, 207, 983, 171, 992, 503, 237, 382, 249, 675, 402, 254, 223, 164, 214, 191, 831, 218, 202, 232, 124, 249, 160, 251, 217, 717, 78, 561, 1627, 256, 386, 225, 432, 499, 394, 364, 445, 634, 667, 177, 346, 470, 663, 142, 588, 414, 617, 1559, 380, 2520, 1040, 417, 289, 238, 220, 214, 303, 163, 141, 510, 397, 137, 137, 133, 133, 390, 266, 137, 183, 215, 191, 485, 328, 575, 799, 533, 148, 215, 589, 589, 130, 362, 562, 471, 179, 186, 1266, 1456, 521, 1536, 427, 444, 406, 912, 150, 283, 144, 485, 470, 1787, 205, 1268, 796, 658, 306, 3751, 321, 331, 814, 146, 2328, 1226, 922, 237, 206, 198, 250, 283, 46, 59, 53, 52, 60, 49, 54, 56, 3000],
   "dependencies": {
-    "Array.prototype.at": [0, 5, 73, 110, 111, 121, 171, 264],
-    "Array.prototype.concat": [0, 17, 22, 23, 27, 37, 44, 81, 83, 162, 172],
-    "Array.prototype.copyWithin": [0, 5, 10, 41, 73, 110, 111, 121, 173],
-    "Array.prototype.every": [0, 16, 18, 22, 23, 27, 57, 63, 81, 83, 162, 174],
-    "Array.prototype.fill": [0, 5, 11, 73, 110, 111, 121, 175],
-    "Array.prototype.filter": [0, 16, 17, 22, 23, 27, 57, 63, 81, 83, 162, 176],
-    "Array.prototype.find": [0, 5, 16, 22, 23, 27, 57, 63, 73, 81, 83, 110, 111, 121, 162, 180],
-    "Array.prototype.findIndex": [0, 5, 16, 22, 23, 27, 57, 63, 73, 81, 83, 110, 111, 121, 162, 177],
-    "Array.prototype.findLast": [0, 5, 15, 57, 63, 73, 110, 111, 121, 179, 266],
-    "Array.prototype.findLastIndex": [0, 5, 15, 57, 63, 73, 110, 111, 121, 178, 265],
-    "Array.prototype.flat": [0, 22, 23, 27, 44, 54, 57, 63, 81, 83, 162, 182],
-    "Array.prototype.flatMap": [0, 22, 23, 27, 44, 54, 57, 63, 81, 83, 162, 181],
-    "Array.prototype.forEach": [0, 12, 16, 18, 22, 23, 27, 57, 63, 81, 83, 162, 183],
-    "Array.from": [0, 13, 24, 25, 27, 37, 57, 63, 66, 67, 80, 83, 93, 162, 184],
-    "Array.prototype.includes": [0, 5, 73, 110, 111, 121, 185],
-    "Array.prototype.indexOf": [0, 18, 63, 186],
-    "Array.isArray": [0, 81, 187],
-    "Array.prototype.join": [0, 18, 188],
-    "Array.prototype.map": [0, 16, 17, 22, 23, 27, 57, 63, 81, 83, 162, 189],
-    "Array.of": [0, 27, 37, 83, 162, 190],
-    "Array.prototype.slice": [0, 17, 20, 27, 37, 81, 83, 162, 191],
-    "Array.prototype.some": [0, 16, 18, 22, 23, 27, 57, 63, 81, 83, 162, 192],
-    "Array.prototype.sort": [0, 18, 20, 21, 27, 41, 46, 47, 50, 162, 163, 193],
-    "Array.prototype.unshift": [0, 19, 41, 44, 81, 194],
-    "Math.acosh": [0, 102, 195],
-    "Math.asinh": [0, 196],
-    "Math.atanh": [0, 197],
-    "Math.cbrt": [0, 105, 198],
-    "Math.clz32": [0, 199],
-    "Math.cosh": [0, 98, 200],
-    "Math.expm1": [0, 98, 201],
-    "Math.fround": [0, 99, 100, 104, 105, 202],
-    "Math.hypot": [0, 203],
-    "Math.imul": [0, 204],
-    "Math.log10": [0, 101, 205],
-    "Math.log1p": [0, 102, 206],
-    "Math.log2": [0, 103, 207],
-    "Math.sign": [0, 105, 208],
-    "Math.sinh": [0, 98, 209],
-    "Math.tanh": [0, 98, 210],
-    "Math.trunc": [0, 211],
-    "Object.assign": [0, 109, 121, 212],
-    "Object.create": [0, 73, 110, 111, 121, 213],
-    "Object.entries": [0, 32, 117, 121, 124, 214],
-    "Object.freeze": [0, 9, 20, 55, 78, 114, 118, 215],
-    "Object.fromEntries": [0, 27, 37, 57, 63, 66, 67, 80, 92, 93, 162, 216],
-    "Object.getOwnPropertyDescriptor": [0, 217],
-    "Object.getOwnPropertyDescriptors": [0, 37, 218],
-    "Object.getPrototypeOf": [0, 32, 117, 219],
-    "Object.hasOwn": [0, 220, 267],
-    "Object.is": [0, 139, 224],
-    "Object.isExtensible": [0, 9, 118, 221],
-    "Object.isFrozen": [0, 9, 222],
-    "Object.isSealed": [0, 9, 223],
-    "Object.keys": [0, 121, 225],
-    "Object.preventExtensions": [0, 9, 20, 55, 78, 114, 118, 226],
-    "Object.seal": [0, 9, 20, 55, 78, 114, 118, 227],
-    "Object.setPrototypeOf": [0, 4, 62, 88, 123, 228],
-    "Object.values": [0, 32, 117, 121, 124, 229],
-    "Promise.any": [0, 25, 27, 51, 57, 63, 66, 67, 80, 92, 93, 107, 127, 128, 129, 130, 162, 231, 269],
-    "Reflect.apply": [0, 56, 232],
-    "Reflect.construct": [0, 3, 20, 27, 56, 59, 73, 83, 110, 111, 121, 162, 233],
-    "Reflect.deleteProperty": [0, 234],
-    "Reflect.get": [0, 32, 84, 117, 237],
-    "Reflect.getOwnPropertyDescriptor": [0, 235],
-    "Reflect.getPrototypeOf": [0, 32, 117, 236],
-    "Reflect.has": [0, 238],
-    "Reflect.isExtensible": [0, 9, 118, 239],
-    "Reflect.ownKeys": [0, 240],
-    "Reflect.preventExtensions": [0, 55, 241],
-    "Reflect.set": [0, 32, 84, 117, 243],
-    "Reflect.setPrototypeOf": [0, 4, 62, 88, 123, 242],
-    "String.prototype.codePointAt": [0, 27, 146, 162, 163, 244],
-    "String.prototype.endsWith": [0, 27, 31, 63, 90, 108, 162, 163, 245],
-    "String.fromCodePoint": [0, 246],
-    "String.prototype.includes": [0, 27, 31, 90, 108, 162, 163, 247],
-    "String.prototype.matchAll": [0, 3, 6, 27, 32, 34, 63, 73, 83, 90, 94, 95, 110, 111, 117, 121, 131, 132, 133, 134, 135, 136, 137, 140, 144, 146, 162, 163, 249, 270],
-    "String.prototype.padEnd": [0, 27, 147, 148, 149, 162, 163, 250],
-    "String.prototype.padStart": [0, 27, 147, 148, 149, 162, 163, 251],
-    "String.raw": [0, 27, 162, 163, 252],
-    "String.prototype.repeat": [0, 27, 149, 162, 163, 253],
-    "String.prototype.replaceAll": [0, 27, 69, 90, 133, 134, 162, 163, 254, 271],
-    "String.prototype.startsWith": [0, 27, 31, 63, 90, 108, 162, 163, 255],
-    "String.prototype.substr": [0, 27, 162, 163, 256],
-    "String.prototype.trim": [0, 27, 151, 153, 162, 163, 170, 261],
-    "String.prototype.trimEnd": [0, 27, 150, 151, 153, 162, 163, 170, 257, 259],
-    "String.prototype.trimStart": [0, 27, 151, 152, 153, 162, 163, 170, 258, 260],
-    "String.prototype.link": [0, 27, 33, 145, 162, 163, 248],
-    "WeakSet": [0, 4, 7, 9, 16, 20, 22, 23, 25, 27, 28, 29, 39, 55, 57, 62, 63, 66, 67, 76, 78, 80, 81, 83, 88, 92, 93, 114, 118, 123, 140, 162, 262, 263],
-    "Promise.allSettled": [0, 25, 27, 51, 57, 63, 66, 67, 80, 92, 93, 107, 127, 128, 129, 130, 162, 230, 268],
-    "focus-visible": [272]
+    "Array.prototype.at": [0, 5, 69, 105, 106, 116, 166, 257],
+    "Array.prototype.concat": [0, 16, 21, 22, 26, 34, 40, 76, 78, 157, 167],
+    "Array.prototype.copyWithin": [0, 5, 9, 37, 69, 105, 106, 116, 168],
+    "Array.prototype.every": [0, 15, 17, 21, 22, 26, 53, 59, 76, 78, 157, 169],
+    "Array.prototype.fill": [0, 5, 10, 69, 105, 106, 116, 170],
+    "Array.prototype.filter": [0, 15, 16, 21, 22, 26, 53, 59, 76, 78, 157, 171],
+    "Array.prototype.find": [0, 5, 15, 21, 22, 26, 53, 59, 69, 76, 78, 105, 106, 116, 157, 175],
+    "Array.prototype.findIndex": [0, 5, 15, 21, 22, 26, 53, 59, 69, 76, 78, 105, 106, 116, 157, 172],
+    "Array.prototype.findLast": [0, 5, 14, 53, 59, 69, 105, 106, 116, 174, 259],
+    "Array.prototype.findLastIndex": [0, 5, 14, 53, 59, 69, 105, 106, 116, 173, 258],
+    "Array.prototype.flat": [0, 21, 22, 26, 40, 50, 53, 59, 76, 78, 157, 177],
+    "Array.prototype.flatMap": [0, 21, 22, 26, 40, 50, 53, 59, 76, 78, 157, 176],
+    "Array.prototype.forEach": [0, 11, 15, 17, 21, 22, 26, 53, 59, 76, 78, 157, 178],
+    "Array.from": [0, 12, 23, 24, 26, 34, 53, 59, 62, 63, 75, 78, 88, 157, 179],
+    "Array.prototype.includes": [0, 5, 69, 105, 106, 116, 180],
+    "Array.prototype.indexOf": [0, 17, 59, 181],
+    "Array.isArray": [0, 76, 182],
+    "Array.prototype.join": [0, 17, 183],
+    "Array.prototype.map": [0, 15, 16, 21, 22, 26, 53, 59, 76, 78, 157, 184],
+    "Array.of": [0, 26, 34, 78, 157, 185],
+    "Array.prototype.slice": [0, 16, 19, 26, 34, 76, 78, 157, 186],
+    "Array.prototype.some": [0, 15, 17, 21, 22, 26, 53, 59, 76, 78, 157, 187],
+    "Array.prototype.sort": [0, 17, 19, 20, 26, 37, 42, 43, 46, 157, 158, 188],
+    "Array.prototype.unshift": [0, 18, 37, 40, 76, 189],
+    "Math.acosh": [0, 97, 190],
+    "Math.asinh": [0, 191],
+    "Math.atanh": [0, 192],
+    "Math.cbrt": [0, 100, 193],
+    "Math.clz32": [0, 194],
+    "Math.cosh": [0, 93, 195],
+    "Math.expm1": [0, 93, 196],
+    "Math.fround": [0, 94, 95, 99, 100, 197],
+    "Math.hypot": [0, 198],
+    "Math.imul": [0, 199],
+    "Math.log10": [0, 96, 200],
+    "Math.log1p": [0, 97, 201],
+    "Math.log2": [0, 98, 202],
+    "Math.sign": [0, 100, 203],
+    "Math.sinh": [0, 93, 204],
+    "Math.tanh": [0, 93, 205],
+    "Math.trunc": [0, 206],
+    "Object.assign": [0, 104, 116, 207],
+    "Object.create": [0, 69, 105, 106, 116, 208],
+    "Object.entries": [0, 29, 112, 116, 119, 209],
+    "Object.freeze": [0, 8, 19, 51, 73, 109, 113, 210],
+    "Object.fromEntries": [0, 26, 34, 53, 59, 62, 63, 75, 87, 88, 157, 211],
+    "Object.getOwnPropertyDescriptor": [0, 212],
+    "Object.getOwnPropertyDescriptors": [0, 34, 213],
+    "Object.getPrototypeOf": [0, 29, 112, 214],
+    "Object.hasOwn": [0, 215, 260],
+    "Object.is": [0, 134, 219],
+    "Object.isExtensible": [0, 8, 113, 216],
+    "Object.isFrozen": [0, 8, 217],
+    "Object.isSealed": [0, 8, 218],
+    "Object.keys": [0, 116, 220],
+    "Object.preventExtensions": [0, 8, 19, 51, 73, 109, 113, 221],
+    "Object.seal": [0, 8, 19, 51, 73, 109, 113, 222],
+    "Object.setPrototypeOf": [0, 4, 58, 83, 118, 223],
+    "Object.values": [0, 29, 112, 116, 119, 224],
+    "Promise.any": [0, 24, 26, 47, 53, 59, 62, 63, 75, 87, 88, 102, 122, 123, 124, 125, 157, 226, 262],
+    "Reflect.apply": [0, 52, 227],
+    "Reflect.construct": [0, 3, 19, 26, 52, 55, 69, 78, 105, 106, 116, 157, 228],
+    "Reflect.deleteProperty": [0, 229],
+    "Reflect.get": [0, 29, 79, 112, 232],
+    "Reflect.getOwnPropertyDescriptor": [0, 230],
+    "Reflect.getPrototypeOf": [0, 29, 112, 231],
+    "Reflect.has": [0, 233],
+    "Reflect.isExtensible": [0, 8, 113, 234],
+    "Reflect.ownKeys": [0, 235],
+    "Reflect.preventExtensions": [0, 51, 236],
+    "Reflect.set": [0, 29, 79, 112, 238],
+    "Reflect.setPrototypeOf": [0, 4, 58, 83, 118, 237],
+    "String.prototype.codePointAt": [0, 26, 141, 157, 158, 239],
+    "String.prototype.endsWith": [0, 26, 28, 59, 85, 103, 157, 158, 240],
+    "String.fromCodePoint": [0, 241],
+    "String.prototype.includes": [0, 26, 28, 85, 103, 157, 158, 242],
+    "String.prototype.matchAll": [0, 3, 6, 26, 29, 31, 59, 69, 78, 85, 89, 90, 105, 106, 112, 116, 126, 127, 128, 129, 130, 131, 132, 135, 139, 141, 157, 158, 244, 263],
+    "String.prototype.padEnd": [0, 26, 142, 143, 144, 157, 158, 245],
+    "String.prototype.padStart": [0, 26, 142, 143, 144, 157, 158, 246],
+    "String.raw": [0, 26, 157, 158, 247],
+    "String.prototype.repeat": [0, 26, 144, 157, 158, 248],
+    "String.prototype.replaceAll": [0, 26, 65, 85, 128, 129, 157, 158, 249, 264],
+    "String.prototype.startsWith": [0, 26, 28, 59, 85, 103, 157, 158, 250],
+    "String.prototype.substr": [0, 26, 157, 158, 251],
+    "String.prototype.trim": [0, 26, 146, 148, 157, 158, 165, 256],
+    "String.prototype.trimEnd": [0, 26, 145, 146, 148, 157, 158, 165, 252, 254],
+    "String.prototype.trimStart": [0, 26, 146, 147, 148, 157, 158, 165, 253, 255],
+    "String.prototype.link": [0, 26, 30, 140, 157, 158, 243],
+    "Promise.allSettled": [0, 24, 26, 47, 53, 59, 62, 63, 75, 87, 88, 102, 122, 123, 124, 125, 157, 225, 261],
+    "focus-visible": [265]
   },
-  "maxSize": 167439
+  "maxSize": 159806
 }
diff --git a/core/audits/byte-efficiency/polyfill-module-data.json b/core/audits/byte-efficiency/polyfill-module-data.json
@@ -627,13 +627,6 @@
     ],
     "corejs": true
   },
-  {
-    "name": "WeakSet",
-    "modules": [
-      "es.weak-set"
-    ],
-    "corejs": true
-  },
   {
     "name": "Array.prototype.at",
     "modules": [
diff --git a/core/scripts/legacy-javascript/create-polyfill-module-data.js b/core/scripts/legacy-javascript/create-polyfill-module-data.js
@@ -66,6 +66,14 @@ const modulesToSkip = [
   'es.string.sub',
   'es.string.sup',
 
+  // Internals of core-js@3 currently emit the code for these polyfills even if not needed
+  // by the target environment.
+  // Example: https://github.com/zloirock/core-js/blob/2da152ff2b23d483be6e2e30e4fcb93582bd9be7/packages/core-js/internals/composite-key.js#L2-L3
+  'es.map',
+  'es.set',
+  'es.weak-map',
+  'es.weak-set',
+
   // Skip some tricky stuff. Would be good to reduce this array.
   'es.symbol',
   'es.symbol.description',
@@ -113,7 +121,6 @@ const modulesToSkip = [
   'es.global-this',
   'es.json.stringify',
   'es.json.to-string-tag',
-  'es.map',
   'es.math.to-string-tag',
   'es.number.constructor',
   'es.number.epsilon',
@@ -150,7 +157,6 @@ const modulesToSkip = [
   'es.regexp.sticky',
   'es.regexp.test',
   'es.regexp.to-string',
-  'es.set',
   'es.string.at-alternative',
   'es.string.iterator',
   'es.string.match',
@@ -195,7 +201,6 @@ const modulesToSkip = [
   'es.typed-array.to-locale-string',
   'es.typed-array.to-string',
   'es.unescape',
-  'es.weak-map',
   'esnext.aggregate-error',
   'esnext.global-this',
   'esnext.typed-array.at',
diff --git a/core/scripts/legacy-javascript/summary-signals-nomaps.json b/core/scripts/legacy-javascript/summary-signals-nomaps.json
@@ -1,5 +1,5 @@
 {
-  "totalSignals": 270,
+  "totalSignals": 267,
   "variantsMissingSignals": [
     "baseline_true_bugfixes_false",
     "baseline_true_bugfixes_true"
@@ -98,8 +98,7 @@
         "String.prototype.substr",
         "String.prototype.trimEnd",
         "String.prototype.trimStart",
-        "String.prototype.trim",
-        "WeakSet"
+        "String.prototype.trim"
       ]
     },
     {
@@ -814,14 +813,6 @@
         "String.raw"
       ]
     },
-    {
-      "group": "core-js-3-only-polyfill",
-      "name": "WeakSet",
-      "dir": "core-js-3-only-polyfill/WeakSet",
-      "signals": [
-        "WeakSet"
-      ]
-    },
     {
       "group": "core-js-3-preset-env",
       "name": "baseline_false_bugfixes_false",
@@ -910,7 +901,6 @@
         "String.prototype.trimEnd",
         "String.prototype.trimStart",
         "String.prototype.trim",
-        "WeakSet",
         "@babel/plugin-transform-classes",
         "@babel/plugin-transform-regenerator",
         "@babel/plugin-transform-spread"
diff --git a/core/scripts/legacy-javascript/summary-signals.json b/core/scripts/legacy-javascript/summary-signals.json
@@ -1,5 +1,5 @@
 {
-  "totalSignals": 270,
+  "totalSignals": 267,
   "variantsMissingSignals": [
     "baseline_true_bugfixes_false",
     "baseline_true_bugfixes_true"
@@ -98,8 +98,7 @@
         "String.prototype.substr",
         "String.prototype.trimEnd",
         "String.prototype.trimStart",
-        "String.prototype.trim",
-        "WeakSet"
+        "String.prototype.trim"
       ]
     },
     {
@@ -814,14 +813,6 @@
         "String.raw"
       ]
     },
-    {
-      "group": "core-js-3-only-polyfill",
-      "name": "WeakSet",
-      "dir": "core-js-3-only-polyfill/WeakSet",
-      "signals": [
-        "WeakSet"
-      ]
-    },
     {
       "group": "core-js-3-preset-env",
       "name": "baseline_false_bugfixes_false",
@@ -910,7 +901,6 @@
         "String.prototype.trimEnd",
         "String.prototype.trimStart",
         "String.prototype.trim",
-        "WeakSet",
         "@babel/plugin-transform-classes",
         "@babel/plugin-transform-regenerator",
         "@babel/plugin-transform-spread"
diff --git a/core/scripts/legacy-javascript/summary-sizes.txt b/core/scripts/legacy-javascript/summary-sizes.txt
@@ -1,8 +1,7 @@
 all-legacy-polyfills
-  191735       all-legacy-polyfills-core-js-3/main.bundle.min.js
+  182535       all-legacy-polyfills-core-js-3/main.bundle.min.js
 
 core-js-3-only-polyfill
-  62600        WeakSet/main.bundle.min.js
   59387        String-prototype-matchAll/main.bundle.min.js
   48198        Promise-any/main.bundle.min.js
   48015        Promise-allSettled/main.bundle.min.js
diff --git a/core/test/audits/byte-efficiency/legacy-javascript-test.js b/core/test/audits/byte-efficiency/legacy-javascript-test.js
@@ -175,14 +175,18 @@ Map {
       'Object.defineProperty(String.prototype, "repeat", function() {})',
       'Object.defineProperty(String.prototype, "repeat", function() {})',
       'String.raw = function() {}',
+
       // es-shims (object.entries)
       'no(Object,{entries:r},{entries:function',
       'no(Array.prototype,{findLast:r},{findLast:function',
+
       // Class polyfills.
-      'Object.defineProperty(window, \'WeakSet\', function() {})',
-      'WeakSet = function() {}',
-      'window.WeakSet = function() {}',
-      'function WeakSet() {}',
+      // Currently not used. See create-polyfill-module-data.js
+      // 'Object.defineProperty(window, \'WeakSet\', function() {})',
+      // 'WeakSet = function() {}',
+      // 'window.WeakSet = function() {}',
+      // Collection polyfills.
+      // 'collection("WeakSet",(function(init){return',
     ];
     const variants = createVariants(codeSnippets);
     const scripts = variants.map((code, i) => {
