在angular 2文档,*和模板中,我们知道*ngIf,*ngSwitch,*ngFor可以扩展为模板标记.我的问题是:
我觉得ngIf还是ngFor没有*也可以翻译并通过角引擎扩展到模板标签.那么为什么要*在角度2中设计一个奇怪的符号asterisk()呢？
<hero-detail *ngIf="currentHero" [hero]="currentHero"></hero-detail>
<template [ngIf]="currentHero">
<hero-detail [hero]="currentHero"></hero-detail>
</template>
Angular 2高级测试文档:
userServiceStub = {
isLoggedIn: true,
user: { name: 'Test User'}
};
TestBed.configureTestingModule({
declarations: [ WelcomeComponent ],
// providers: [ UserService ] // NO! Don't provide the real service!
// Provide a test-double instead
providers: [ {provide: UserService, useValue: userServiceStub } ]
});
fixture = TestBed.createComponent(WelcomeComponent);
comp = fixture.componentInstance;
// UserService actually injected into the component
userService = fixture.debugElement.injector.get(UserService);
componentUserService = userService;
// UserService from the root injector
userService = TestBed.get(UserService);
看来我们显式创建的服务,userService表单injector.get()和userServiceStub是不同的Object.
it('stub object and injected UserService should not …原始css有@import关键字,可以包含外部css文件.
那么,来自SASS/SCSS @import的这个@import有什么区别？
根据角度的最新版本,@ angular/forms导出以下内容:
export {FormControlDirective} from './directives/reactive_directives/form_control_directive';
export {FormControlName} from './directives/reactive_directives/form_control_name';
export {FormGroupDirective} from './directives/reactive_directives/form_group_directive';
export {FormArrayName} from './directives/reactive_directives/form_group_name';
export {FormGroupName} from './directives/reactive_directives/form_group_name';
FormContolName并且FormControlDirective,FormGroupName和FormGroupDirective,但FormArrayName没有FormArrayDirective,为什么？
我在 angular2-seed 中发现了一些奇怪的符号 <%%>，<%%> 是干什么用的？
https://github.com/AngularClass/angular2-webpack-starter/blob/master/src/index.html
<!DOCTYPE html>
<html lang="">
<head>
<meta charset="utf-8">
<meta http-equiv="x-ua-compatible" content="ie=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title><%= htmlWebpackPlugin.options.title %></title>
<meta name="description" content="<%= htmlWebpackPlugin.options.title %>">
<% if (webpackConfig.htmlElements.headTags) { %>
<!-- Configured Head Tags -->
<%= webpackConfig.htmlElements.headTags %>
<% } %>
<!-- base url -->
<base href="<%= htmlWebpackPlugin.options.metadata.baseUrl %>">
</head>
<body>
<app>
Loading...
</app>
.....
<% if (htmlWebpackPlugin.options.metadata.isDevServer && htmlWebpackPlugin.options.metadata.HMR !== true) { %>
<!-- Webpack Dev Server reload -->
<script src="/webpack-dev-server.js"></script>
<% } %>
</body>
</html>