MDL-67536 libraries: replace babel-polyfill with core-js

lib/babel-polyfill/readme_moodle.txt

@@ -1,6 +0,0 @@
-Installation instructions can be found at https://babeljs.io/docs/en/babel-polyfill.html#usage-in-browser
-
-The steps are essentially:
-1.) npm install @babel/polyfill
-2.) copy polyfill.js and polyfill.min.js from the "dist" folder from the npm release into lib/babel-polyfill/
-3.) npm uninstall --save @babel/polyfill (don't want to include that with Moodle package.json)

lib/outputrequirementslib.php

@@ -1614,14 +1614,6 @@ EOF;
         // First the skip links.
         $output = $renderer->render_skip_links($this->skiplinks);
 
-        // The polyfill needs to load before the other JavaScript in order to make sure
-        // that we have access to the functions it provides.
-        if (empty($CFG->cachejs)) {
-            $output .= html_writer::script('', $this->js_fix_url('/lib/babel-polyfill/polyfill.js'));
-        } else {
-            $output .= html_writer::script('', $this->js_fix_url('/lib/babel-polyfill/polyfill.min.js'));
-        }
-
         // Include the Polyfills.
         $output .= html_writer::script('', $this->js_fix_url('/lib/polyfills/polyfill.js'));
 

lib/polyfills/readme_moodle.txt

@@ -1,15 +1,23 @@
 The steps are essentially:
-1) Install mdn-polyfills and url-polyfill packages
+1) Install required packages
 
-    npm install --no-save mdn-polyfills url-polyfill
+    npm install --no-save mdn-polyfills url-polyfill regenerator-runtime core-js-bundle
 
 2) Join them all together:
 
     cd node_modules/mdn-polyfills
     cat CustomEvent.* Element.* Function.* HTMLCanvasElement.* MouseEvent.* Node.prototype.* NodeList.* > ../../lib/polyfills/polyfill.js
+
     cd ../url-polyfill/
     cat url-polyfill.min.js >> ../../lib/polyfills/polyfill.js
 
+    cd ../regenerator-runtime
+    cat runtime.js >> ../../lib/polyfills/polyfill.js
+
+    cd ../core-js-bundle
+    cat minified.js >> ../../lib/polyfills/polyfill.js
+    sed -i '/\/\/\# sourceMappingURL=minified.js.map/d' ../../lib/polyfills/polyfill.js
+
 3) Uninstall the packages again
 
-    npm uninstall --no-save mdn-polyfills url-polyfill
+    npm uninstall --no-save mdn-polyfills url-polyfill regenerator-runtime core-js-bundle

lib/thirdpartylibs.xml

@@ -303,10 +303,16 @@
     <licenseversion>3-Clause</licenseversion>
   </library>
   <library>
-    <location>babel-polyfill</location>
-    <name>babel-polyfill</name>
+    <location>polyfills</location>
+    <name>regenerator-runtime</name>
     <license>MIT</license>
-    <version>7.7.0</version>
+    <version>0.13.7</version>
+  </library>
+  <library>
+    <location>polyfills</location>
+    <name>core-js-bundle</name>
+    <license>MIT</license>
+    <version>3.15.0</version>
   </library>
   <library>
     <location>polyfills</location>

lib/upgrade.txt

@@ -22,6 +22,7 @@ information provided here is intended especially for developers.
 * The core/event::getLegacyEvents() function has been deprecated and should no longer be used.
 * Typo3 has now been removed. Use native mbstring or iconv functions.
 * A new index has been added on mdl_user_preferences.name. This upgrade step might take some time on big sites.
+* @babel/polyfill has been removed in favour of corejs@3
 
 === 3.11 ===
 * PHPUnit has been upgraded to 9.5 (see MDL-71036 for details).