@angular/cli：如何让@angular/cli生成的项目兼容IE9/1

一个恶心的事情是：@/cli 生成的项目默认不能很好地支持IE，9/10/11都不行。

好消息是：@/cli默认生成了.ts文件，只要简单几个步骤就可以支持了。

第一步：用@/cli创建项目

ng new ie-test
cd ie-test
ng serve

打开你的浏览器，访问:4200，很顺利地看到以下界面：

然后，打开IE，很自然地报错了：

仔细看报错信息，你就可以发现，这是因为IE不支持ES6里面给Array扩展的for...of循环导致的。

浏览器对ES6的支持程度，你可以在MDN上查到详细的信息：

第二步：解决问题

打开@/cli自动生成的.ts文件，你可以看到这样的内容：

/*** 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/docs/ts/latest/guide/browser-support.html*//**************************************************************************************************** BROWSER POLYFILLS*//** IE9, IE10 and IE11 requires all of the following polyfills. **/
import 'core-js/es6/symbol';
import 'core-js/es6/object';
import 'core-js/es6/function';
import 'core-js/es6/parse-int';
import 'core-js/es6/parse-float';
import 'core-js/es6/number';
import 'core-js/es6/math';
import 'core-js/es6/string';
import 'core-js/es6/date';
import 'core-js/es6/array';
import 'core-js/es6/regexp';
import 'core-js/es6/map';
import 'core-js/es6/weak-map';
import 'core-js/es6/set';/** IE10 and IE11 requires the following for NgClass support on SVG elements */
import 'classlist.js';  // Run `npm install --save classlist.js`.
/** IE10 and IE11 requires the following for the Reflect API. */
import 'core-js/es6/reflect';/** Evergreen browsers require these. **/
// Used for reflect-metadata in JIT. If you use AOT (and only Angular decorators), you can remove.
import 'core-js/es7/reflect';/*** Required to support Web Animations `@angular/platform-browser/animations`.* Needed for: All but Chrome, Firefox and Opera. http://caniuse.com/#feat=web-animation**/
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*/// (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__BLACK_LISTED_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*/

对于这一坨在干什么，你仔细看每一行代码后面的注释就知道了。

这里有一个小注意点，有两个依赖需要你手动安装：

npm install --save classlist.js
npm install --save web-animations-js

装完之后重新：

ng serve

然后你就可以在IE里面哈皮地看到这个了：