fix(docs-infra): fix angular.io on browsers that support Custom Elements but not ES2015 (#41183)

Before #41162, angular.io was broken on IE 11 due to missing a polyfill
for an API (`Reflect.construct()`) needed by the Custom Elements ES5
shim. #41162 tried to fix this by loading the necessary polyfill
(`es.reflect.construct.js`) on browsers that do not support ES2015
modules (including IE 11).

It turns out that the fix in #41162 was itself broken, because the
`es.reflect.consruct.js` script (included directly in the page via a
`<script>` tag) was in CommonJS format (which cannot run in the browser
as is). By chance, this still allowed browsers that supported neither
Custom Elements nor ES2015 modules (such as IE 11) to work correctly as
a side-effect of loading the `@webcomponents/custom-elements` polyfill
after the Custom Elements ES5 shim (`native-shim.js`). However, on the
few browsers that natively support Custom Elements but not ES2015
modules, angular.io would still be broken.

This commit correctly fixes angular.io on all browsers by properly
bundling the polyfills and transpiling to ES5.

Implementation-wise, we use [esbuild][1] for bundling the polyfills (and
converting from CommonJS to a browser-compatible, IIFE-based format) and
[swc][2] for downleveling the code to ES5 (since `esbuild` only supports
ES2015+).

[1]: https://esbuild.github.io/
[2]: https://swc.rs/

PR Close #41183

aio/angular.json

@@ -44,17 +44,7 @@
               "src/assets",
               "src/generated",
               "src/pwa-manifest.json",
-              "src/google385281288605d160.html",
+              "src/google385281288605d160.html"
-              {
-                "glob": "native-shim.js",
-                "input": "node_modules/@webcomponents/custom-elements/src",
-                "output": "/assets/js"
-              },
-              {
-                "glob": "es.reflect.construct.js",
-                "input": "node_modules/core-js/modules",
-                "output": "/assets/js"
-              }
             ],
             "styles": [
               "src/styles/main.scss"
@@ -156,17 +146,7 @@
               "src/assets",
               "src/generated",
               "src/pwa-manifest.json",
-              "src/google385281288605d160.html",
+              "src/google385281288605d160.html"
-              {
-                "glob": "native-shim.js",
-                "input": "node_modules/@webcomponents/custom-elements/src",
-                "output": "/assets/js"
-              },
-              {
-                "glob": "es.reflect.construct.js",
-                "input": "node_modules/core-js/modules",
-                "output": "/assets/js"
-              }
             ],
             "styles": [
               "src/styles/main.scss"

aio/ngsw-config.json

@@ -13,8 +13,6 @@
           "/assets/js/*.js",
           "/*.css",
           "/*.js",
-          "!/assets/js/es.reflect.construct.js",
-          "!/assets/js/native-shim.js",
           "!/*-es5*.js"
         ],
         "urls": [
@@ -41,8 +39,7 @@
       "resources": {
         "files": [
           "/assets/images/favicons/**",
-          "/assets/js/es.reflect.construct.js",
+          "/generated/js/custom-elements-es5-polyfills.js",
-          "/assets/js/native-shim.js",
           "/*-es5*.js",
           "!/**/_unused/**"
         ]

aio/package.json

@@ -77,8 +77,10 @@
     "~~audit-web-app": "node scripts/audit-web-app",
     "~~check-env": "node scripts/check-environment",
     "~~clean-generated": "node --eval \"require('shelljs').rm('-rf', 'src/generated')\"",
+    "pre~~build": "yarn ~~build-ce-es5-polyfills",
     "~~build": "ng build --configuration=stable",
     "post~~build": "yarn build-404-page",
+    "~~build-ce-es5-polyfills": "esbuild src/custom-elements-es5-polyfills.js --bundle --minify | swc --config=minify=true --filename=custom-elements-es5-polyfills.js --out-file=src/generated/js/custom-elements-es5-polyfills.js --no-swcrc",
     "~~light-server": "light-server --bind=localhost --historyindex=/index.html --no-reload"
   },
   "//engines-comment": "Keep this in sync with /package.json and /aio/tools/examples/shared/package.json",
@@ -109,6 +111,8 @@
     "@angular-devkit/build-angular": "0.1102.2",
     "@angular/cli": "11.2.2",
     "@angular/compiler-cli": "11.2.3",
+    "@swc/cli": "^0.1.35",
+    "@swc/core": "^1.2.50",
     "@types/jasmine": "~3.6.0",
     "@types/lunr": "^2.3.2",
     "@types/node": "^12.7.9",
@@ -124,6 +128,7 @@
     "dgeni": "^0.4.13",
     "dgeni-packages": "^0.28.4",
     "entities": "^1.1.1",
+    "esbuild": "^0.9.0",
     "eslint": "^3.19.0",
     "eslint-plugin-jasmine": "^2.2.0",
     "find-free-port": "^2.0.0",

aio/src/custom-elements-es5-polyfills.js

@@ -0,0 +1,15 @@
+/**
+ * Custom Elements polyfills for browsers that natively support Custom Elements but not ES2015
+ * modules.
+ *
+ * NOTE:
+ * Chrome, Firefox and Safari should not need these, because they added support for ES2015 modules
+ * before Custom Elements. It is still required for some other (less common) browsers:
+ *   - UC browser for android 11.8 (~3.5% global usage)
+ *   - Samsung browser 5.0-8.1 (~0.43% global usage)
+ *   - Opera 41-47 (~0.02% global usage)
+ */
+// @ts-nocheck
+
+require('core-js/modules/es.reflect.construct');  // Required by `native-shim.js`.
+require('@webcomponents/custom-elements/src/native-shim');

aio/src/index.html

@@ -110,16 +110,16 @@
   </noscript>
 
   <!--
-    Custom Element ES5 shim. Required for browsers that natively support Custom Elements, but do not
+    Custom Elements polyfills required for browsers that natively support Custom Elements but not
-    support ES2015 modules.
+    ES2015 modules. (See `custom-elements-es5-polyfills.js` for more info.)
-    NOTE: Chrome, Firefox and Safari should not need this, because they added support for ES2015
+
-          modules before Custom Elements. It is still required for some other (less common) browsers:
+    NOTE:
-          - UC browser for android 11.8 (~3.5% global usage)
+    The polyfills here will be loaded before the ones in `polyfills.ts` (including
-          - Samsung browser 5.0-8.1 (~0.43% global usage)
+    `@webcomponents/custom-elements`). This is fine, because the polyfills here are only needed on
-          - Opera 41-47 (~0.02% global usage)
+    browsers that natively support Custom Elements, on which `@webcomponents/custom-elements` will
+    be a no-op (so the order of loading does not matter).
   -->
-  <script src="assets/js/es.reflect.construct.js" nomodule></script>;
+  <script src="generated/js/custom-elements-es5-polyfills.js" nomodule></script>
-  <script src="assets/js/native-shim.js" nomodule></script>;
 
 </body>
 

aio/yarn.lock

@@ -1603,6 +1603,11 @@
     call-me-maybe "^1.0.1"
     glob-to-regexp "^0.3.0"
 
+"@napi-rs/triples@^1.0.2":
+  version "1.0.2"
+  resolved "https://registry.yarnpkg.com/@napi-rs/triples/-/triples-1.0.2.tgz#2ce4c6a78568358772008f564ee5009093d20a19"
+  integrity sha512-EL3SiX43m9poFSnhDx4d4fn9SSaqyO2rHsCNhETi9bWPmjXK3uPJ0QpPFtx39FEdHcz1vJmsiW41kqc0AgvtzQ==
+
 "@ngtools/webpack@11.2.2":
   version "11.2.2"
   resolved "https://registry.yarnpkg.com/@ngtools/webpack/-/webpack-11.2.2.tgz#647862ed19761796c7f84d5fb3305661d2a3af67"
@@ -1612,6 +1617,14 @@
     enhanced-resolve "5.7.0"
     webpack-sources "2.2.0"
 
+"@node-rs/helper@^1.0.0":
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/@node-rs/helper/-/helper-1.1.0.tgz#4fcbbebae3b81932d1ff3e431c7cd3886b504742"
+  integrity sha512-r43YnnrY5JNzDuXJdW3sBJrKzvejvFmFWbiItUEoBJsaPzOIWFMhXB7i5j4c9EMXcFfxveF4l7hT+rLmwtjrVQ==
+  dependencies:
+    "@napi-rs/triples" "^1.0.2"
+    tslib "^2.1.0"
+
 "@nodelib/fs.scandir@2.1.3":
   version "2.1.3"
   resolved "https://registry.yarnpkg.com/@nodelib/fs.scandir/-/fs.scandir-2.1.3.tgz#3a582bdb53804c6ba6d146579c46e52130cf4a3b"
@@ -1778,6 +1791,80 @@
   resolved "https://registry.yarnpkg.com/@sindresorhus/is/-/is-0.14.0.tgz#9fb3a3cf3132328151f353de4632e01e52102bea"
   integrity sha512-9NET910DNaIPngYnLLPeg+Ogzqsi9uM4mSboU5y6p8S5DzMTVEsJZrawi+BoDNUVBa2DhJqQYUFvMDfgU062LQ==
 
+"@swc/cli@^0.1.35":
+  version "0.1.35"
+  resolved "https://registry.yarnpkg.com/@swc/cli/-/cli-0.1.35.tgz#e939fd374e889e3329ebdc48988e9e489d06f002"
+  integrity sha512-jjgfm8s+ueNAS8QaStpEXctn0O0AVfRR1vAocsFQyLysQkmbsnp8OyajaKgaLSUsdf4ZWlF8pKATPUPp869UEQ==
+  dependencies:
+    commander "^7.1.0"
+    convert-source-map "^1.6.0"
+    glob "^7.1.3"
+    lodash "^4.17.21"
+    slash "3.0.0"
+    source-map "^0.7.3"
+
+"@swc/core-android-arm64@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core-android-arm64/-/core-android-arm64-1.2.50.tgz#763e5ad1a899e2ff0a914c8ac8134e573d8dc733"
+  integrity sha512-aPJGhHqRkNncZnG5fCRhdX9JHGQ7SJBykm7ER/F6nNuvuSTYbuv4wGLYzNVi2UmeSMQQH/9j1D5xcX8STGIgsw==
+
+"@swc/core-darwin-arm64@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core-darwin-arm64/-/core-darwin-arm64-1.2.50.tgz#1ed630edef1b8864d3793e4133988b7281511239"
+  integrity sha512-ginmLsDGswvaENSDxhevBpq63iKAxKtVS0P53b9KvfOhRDtQpnXMIxc3iYeyII8D2QDR0HOQu/c1n2b6sUIuBQ==
+
+"@swc/core-darwin-x64@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core-darwin-x64/-/core-darwin-x64-1.2.50.tgz#2e794feb5071cf4e7e20cedde872f4dfb77cd031"
+  integrity sha512-HJ2CFuzxIXwoo22jHr1ntuveqoHN0hbY7mUTXaRLWh9468TMeGmD20rm7l9FnOsBVH9m9psHGpOVNOUSEXg6tw==
+
+"@swc/core-linux-arm-gnueabihf@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core-linux-arm-gnueabihf/-/core-linux-arm-gnueabihf-1.2.50.tgz#c7b9e2b35c7d9997004d6138c1c8115e14744cb7"
+  integrity sha512-y1rsaqmbO/rezCifX30ilqTKaeN4yp0pDpHri6hAMKqHOzNGZTrY7p3nmiCd425gFVpM72gcGNrDqbt9IqeOPA==
+
+"@swc/core-linux-arm64-gnu@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core-linux-arm64-gnu/-/core-linux-arm64-gnu-1.2.50.tgz#1f41ac1fae0438641773098f254c9e1d72563d1f"
+  integrity sha512-eh1xpvPNoXiZBrkKLoM1JDXAH5U7zK+kebC7lXsPjPuPVGENfknAoT3oQvyohWnE7pf1nOPBiDX7wOT4T2e1Pw==
+
+"@swc/core-linux-x64-gnu@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core-linux-x64-gnu/-/core-linux-x64-gnu-1.2.50.tgz#57ca45b5b5e67a12ff90b5f50a23559be65840e6"
+  integrity sha512-2I5OX66FQejeiJ4fuPS18AQieVk6H8Z2LfOgCuDMK2ZRQdc3gBe1rYVhZyCGdYXQ76mUlo6+phSy5qI63d172Q==
+
+"@swc/core-linux-x64-musl@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core-linux-x64-musl/-/core-linux-x64-musl-1.2.50.tgz#c9225ec94618e75a5260264db7cd3122930e68f1"
+  integrity sha512-370yPM7+8tzEdiV3Y+RzkzukRfYeDiOS6oRCtpTqGmfh9RUhxyKQFM/gYRi77Qpgq6LnvY1eUQh+WrioCAztXg==
+
+"@swc/core-win32-ia32-msvc@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core-win32-ia32-msvc/-/core-win32-ia32-msvc-1.2.50.tgz#8aca2e009d49f2cff44fe924115104565ce59d5c"
+  integrity sha512-sQOXq79ge8Bv07rh1bHZwiH5qXg8do28HdzhI8/VaFAh3K+8zTqOdF9DuOlf0Z/sE23znbbQcp3Hz30+5jhgWg==
+
+"@swc/core-win32-x64-msvc@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core-win32-x64-msvc/-/core-win32-x64-msvc-1.2.50.tgz#383ac624bdf0d7865013c6482392319afe2e8462"
+  integrity sha512-NmxSnkj7PYkN+e060tf0LR7knrdCzUobSmQrMwWlaC5dACHREFlo00mocL8AwB3WOZKvNp4MQv1cH3EaGbIpKw==
+
+"@swc/core@^1.2.50":
+  version "1.2.50"
+  resolved "https://registry.yarnpkg.com/@swc/core/-/core-1.2.50.tgz#d70daed948c9bb0ba8084e804e7fb2b1fcf0e19c"
+  integrity sha512-v4geRnqPqNBOAhWIT0ntcbw09mOxNy5XaGp4Nulxefpdpr8QUxPa1/9fLRPAbYjojT8yiqDtcLdx+yk+stFhpA==
+  dependencies:
+    "@node-rs/helper" "^1.0.0"
+  optionalDependencies:
+    "@swc/core-android-arm64" "^1.2.50"
+    "@swc/core-darwin-arm64" "^1.2.50"
+    "@swc/core-darwin-x64" "^1.2.50"
+    "@swc/core-linux-arm-gnueabihf" "^1.2.50"
+    "@swc/core-linux-arm64-gnu" "^1.2.50"
+    "@swc/core-linux-x64-gnu" "^1.2.50"
+    "@swc/core-linux-x64-musl" "^1.2.50"
+    "@swc/core-win32-ia32-msvc" "^1.2.50"
+    "@swc/core-win32-x64-msvc" "^1.2.50"
+
 "@szmarczak/http-timer@^1.1.2":
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/@szmarczak/http-timer/-/http-timer-1.1.2.tgz#b1665e2c461a2cd92f4c1bbf50d5454de0d4b421"
@@ -3950,6 +4037,11 @@ commander@^4.0.1:
   resolved "https://registry.yarnpkg.com/commander/-/commander-4.1.1.tgz#9fd602bd936294e9e9ef46a3f4d6964044b18068"
   integrity sha512-NOKm8xhkzAjzFx8B2v5OAHT+u5pRQc2UCa2Vq9jYL/31o2wi9mxBA7LIFs3sV5VSC49z6pEhfbMULvShKj26WA==
 
+commander@^7.1.0:
+  version "7.1.0"
+  resolved "https://registry.yarnpkg.com/commander/-/commander-7.1.0.tgz#f2eaecf131f10e36e07d894698226e36ae0eb5ff"
+  integrity sha512-pRxBna3MJe6HKnBGsDyMv8ETbptw3axEdYHoqNh7gu5oDcew8fs0xnivZGm06Ogk8zGAJ9VX+OPEr2GXEQK4dg==
+
 commondir@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/commondir/-/commondir-1.0.1.tgz#ddd800da0c66127393cca5950ea968a3aaf1253b"
@@ -4113,7 +4205,7 @@ content-type@^1.0.4, content-type@~1.0.4:
   resolved "https://registry.yarnpkg.com/content-type/-/content-type-1.0.4.tgz#e138cc75e040c727b1966fe5e5f8c9aee256fe3b"
   integrity sha512-hIP3EEPs8tB9AT1L+NUqtwOAps4mk2Zob89MWXMHjHWg9milF/j4osnnQLXBCBFBk/tvIG/tUc9mOUJiPBhPXA==
 
-convert-source-map@1.7.0, convert-source-map@^1.5.1, convert-source-map@^1.7.0:
+convert-source-map@1.7.0, convert-source-map@^1.5.1, convert-source-map@^1.6.0, convert-source-map@^1.7.0:
   version "1.7.0"
   resolved "https://registry.yarnpkg.com/convert-source-map/-/convert-source-map-1.7.0.tgz#17a2cb882d7f77d3490585e2ce6c524424a3a442"
   integrity sha512-4FJkXzKXEDB1snCFZlLP4gpC3JILicCpGbzG9f9G7tGqGCzETQ2hWPrcinA9oU4wtf2biUaEH5065UnMeR33oA==
@@ -5391,6 +5483,11 @@ es6-weak-map@^2.0.1, es6-weak-map@^2.0.2:
     es6-iterator "^2.0.3"
     es6-symbol "^3.1.1"
 
+esbuild@^0.9.0:
+  version "0.9.0"
+  resolved "https://registry.yarnpkg.com/esbuild/-/esbuild-0.9.0.tgz#b8320df85048ed1637c6b59ee52abba248936d3c"
+  integrity sha512-IqYFO7ZKHf0y4uJpJfGqInmSRn8jMPMbyI1W0Y2PSjSjJcVP538tC8TleJAS4Y8QeqwajqBTwFKayWVzYlMIgg==
+
 escalade@^3.1.1:
   version "3.1.1"
   resolved "https://registry.yarnpkg.com/escalade/-/escalade-3.1.1.tgz#d8cfdc7000965c5a0174b4a82eaa5c0552742e40"
@@ -8708,6 +8805,11 @@ lodash@^4.17.19:
   resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.20.tgz#b44a9b6297bcb698f1c51a3545a2b3b368d59c52"
   integrity sha512-PlhdFcillOINfeV7Ni6oF1TAEayyZBoZ8bcshTHqOYJYlrqzRK5hagpagky5o4HfCzzd1TRkXPMFq6cKk9rGmA==
 
+lodash@^4.17.21:
+  version "4.17.21"
+  resolved "https://registry.yarnpkg.com/lodash/-/lodash-4.17.21.tgz#679591c564c3bffaae8454cf0b3df370c3d6911c"
+  integrity sha512-v2kDEe57lecTulaDIuNTPy3Ry4gLGJ6Z1O3vE1krgXZNrsQ+LFTGHVxVjcXPs17LhbZVGedAJv8XZ1tvj5FvSg==
+
 log-symbols@^2.2.0:
   version "2.2.0"
   resolved "https://registry.yarnpkg.com/log-symbols/-/log-symbols-2.2.0.tgz#5740e1c5d6f0dfda4ad9323b5332107ef6b4c40a"
@@ -12337,7 +12439,7 @@ simple-swizzle@^0.2.2:
   dependencies:
     is-arrayish "^0.3.1"
 
-slash@^3.0.0:
+slash@3.0.0, slash@^3.0.0:
   version "3.0.0"
   resolved "https://registry.yarnpkg.com/slash/-/slash-3.0.0.tgz#6539be870c165adbd5240220dbe361f1bc4d4634"
   integrity sha512-g9Q1haeby36OSStwb4ntCGGGaKsaVSjQ68fBxoQcutl5fS1vuY18H3wSt3jFyFtrkx+Kz0V1G85A4MyAdDMi2Q==
@@ -13490,7 +13592,7 @@ ts-pnp@^1.1.6:
   resolved "https://registry.yarnpkg.com/ts-pnp/-/ts-pnp-1.2.0.tgz#a500ad084b0798f1c3071af391e65912c86bca92"
   integrity sha512-csd+vJOb/gkzvcCHgTGSChYpy5f1/XKNsmvBGO4JXS+z1v2HobugDz4s1IeFXM3wZB44uczs+eazB5Q/ccdhQw==
 
-tslib@2.1.0:
+tslib@2.1.0, tslib@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-2.1.0.tgz#da60860f1c2ecaa5703ab7d39bc05b6bf988b97a"
   integrity sha512-hcVC3wYEziELGGmEEXue7D75zbwIIVUMWAVbHItGPx0ziyXxrOMQx4rQEVEV45Ut/1IotuEvwqPopzIOkDMf0A==