使用Angular版本8和差异加载时，在为生产而构建时会创建两个捆绑软件：一个用于支持ES2015 +的现代浏览器的捆绑软件，一个用于仅支持ES5版本的JavaScript的较旧浏览器的捆绑软件。由于较新的浏览器支持ES6模块，因此浏览器会自动加载正确的捆绑软件。 Angular还可以自动创建polyfill文件。
是否可以将专用的polyfill添加到ES5输出包中，因此它们不会在ES2015 +输出包中列出？
Angular提供了一个 polyfills.ts 文件，可以在其中添加polyfills。但是我看不到如何在仅将某些polyfill添加到ES5输出包中的情况下构造该文件的方式。
/**
* This file includes polyfills needed by Angular and is loaded before the app.
* You can add your own extra polyfills to this file.
*
* This file is divided into 2 sections:
* 1. Browser polyfills. These are applied before loading ZoneJS and are sorted by browsers.
* 2. Application imports. Files imported after ZoneJS that should be loaded before your main
* file.
*
* The current setup is for so-called "evergreen" browsers; the last versions of browsers that
* automatically update themselves. This includes Safari >= 10, Chrome >= 55 (including Opera),
* Edge >= 13 on the desktop, and iOS 10 and Chrome on mobile.
*
* Learn more in https://angular.io/guide/browser-support
*/
/***************************************************************************************************
* BROWSER POLYFILLS
*/
/** IE10 and IE11 requires the following for NgClass support on SVG elements */
// import 'classlist.js'; // Run `npm install --save classlist.js`.
/**
* Web Animations `@angular/platform-browser/animations`
* Only required if AnimationBuilder is used within the application and using IE/Edge or Safari.
* Standard animation support in Angular DOES NOT require any polyfills (as of Angular 6.0).
*/
// import 'web-animations-js'; // Run `npm install --save web-animations-js`.
/**
* By default, zone.js will patch all possible macroTask and DomEvents
* user can disable parts of macroTask/DomEvents patch by setting following flags
* because those flags need to be set before `zone.js` being loaded, and webpack
* will put import in the top of bundle, so user need to create a separate file
* in this directory (for example: zone-flags.ts), and put the following flags
* into that file, and then add the following code before importing zone.js.
* import './zone-flags.ts';
*
* The flags allowed in zone-flags.ts are listed here.
*
* The following flags will work for all browsers.
*
* (window as any).__Zone_disable_requestAnimationFrame = true; // disable patch requestAnimationFrame
* (window as any).__Zone_disable_on_property = true; // disable patch onProperty such as onclick
* (window as any).__zone_symbol__UNPATCHED_EVENTS = ['scroll', 'mousemove']; // disable patch specified eventNames
*
* in IE/Edge developer tools, the addEventListener will also be wrapped by zone.js
* with the following flag, it will bypass `zone.js` patch for IE/Edge
*
* (window as any).__Zone_enable_cross_context_check = true;
*
*/
/***************************************************************************************************
* Zone JS is required by default for Angular itself.
*/
import 'zone.js/dist/zone'; // Included with Angular CLI.
/***************************************************************************************************
* APPLICATION IMPORTS
*/