Number toLocaleString 不适用于 Angular 测试答案

【问题标题】：Number toLocaleString not working on Angular' testsNumber toLocaleString 不适用于 Angular 测试
【发布时间】：2020-09-14 14:51:12
【问题描述】：

我的应用程序有以下功能。

convertToPercent(number) {
  if (!number) return 'N/A';
    return Number(number / 100).toLocaleString('pt-br', { style: 'percent' 
  });
}

然后我刚刚创建了以下测试场景

it('Should convertToPercent(10) return "10%" ' , () => { 
    expect(component.convertToPercent(10)).toEqual('10%');
})

但是当我运行测试时，它就坏了，因为 0.1 不等于 10%。

有人知道它是什么吗？

当运行应用程序时，它正在工作。

【问题讨论】：

我创建了一个 FakeComponent 仅包含您的“convertToPercent”函数，然后是一个包含您的测试场景的特定单元测试文件。取得了成功。这很奇怪......
你能告诉我你有哪个版本的 Angular 和 Jasmine @JulienDéramond？
Angular 8.2.14 和 Jasmine 3.4.0。 Angular 7.2.15 和 Jasmine 3.3.1 也很成功。
我第一次尝试使用 Stackblitz 构建一些东西，所以也许我犯了一些错误，但我认为它接近你的环境：stackblitz.com/edit/stackoverflow-63886733。它似乎可以与 Angular 9.0.6、Karma 4.4.1 和 Jasmine 3.5.0 一起使用？
@JulienDéramond 我刚刚发现了这个问题......它正在发生，因为我正在使用幻影 js 运行......然后在幻影浏览器中运行命令，我得到了 0.1 作为答案。所以这不是业力/茉莉花问题，而是我现在正在运行的浏览器。

标签： javascript angular testing jasmine

【解决方案1】：

我刚刚检测到问题是因为默认的 PhantomJS 浏览器不支持默认的 ECMAScript 国际化 API。

要解决这个问题，您可以使用 npm i intl --save-dev 安装 intl 库，然后在 polyfill 文件中启用它。

 * Load `$localize` onto the global scope - used if i18n tags appear in Angular templates.
 */
import '@angular/localize/init';
/**
 * 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
 */
import 'intl';

/**
 * Date, currency, decimal and percent pipes.
 * Needed for: All but Chrome, Firefox, Edge, IE11 and Safari 10
 */
/**
 * Need to import at least one locale-data with intl.
 */
import 'intl/locale-data/jsonp/pt-BR';

其他信息：https://dzone.com/articles/using-phantomjs-with-karma

【讨论】：