我的Angular应用程序无法在Firefox 45.7.0中运行，我在控制台上遇到此错误：
TypeError：这是未定义的。
在最新版本的Firefox中运行正常。还有Chrome，IE 9，IE 10，IE 11，Safari，Opera和Edge。
这是我的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';
/**
* 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
*/
// (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
*/
在我的index.html中：
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
我也定位es5。
如何让这个应用在Firefox 45.7.0中运行？