EventEmitter} from '@angular/core';//子组件中实例化 EventEmitter//用 EventEmitter 和 @Output 装饰器配合使用 <string> 指定类型变量@Output() private outer=newEventEmitter<string>();//子组件通过 EventEmitter 对象 outer 实例广播数据sendParent(){this.outer.emit('msg from child')...
import { Component, OnInit } from '@angular/core'; import { Observable } from 'rxjs/Observable'; @Component({ selector: 'app-example', template: ` <div>{{ value }}</div> ` }) export class ExampleComponent implements OnInit { value: string; ngOnInit() { ...
get('age'); return name && age && name.value === 'lala' && age.value === 12 ? { 'nameAgeInvalid': true } : null; }; @Component({ selector: 'app-reactive-forms', templateUrl: './reactive-forms.component.html', styleUrls: ['./reactive-forms.component.scss'] }) export class ...
import { Component } from '@angular/core'; @Component({ selector: 'app-c', templateUrl: './c.component.html', }) export class CComponent { constructor() {} inputValue: string = ''; send(): void { // 存储数据 window.localStorage.setItem('cValue', this.inputValue); } } 创建D组...
假如我们 select my-child,然后尝试 query my-parent,结果是这样 因为有 Shadow DOM 隔离,my-child 无法直接 query 到 my-parent,唯一的方法是一层一层往上拿 先找到 shadowRoot 然后 .host 才可以越出 Shadow DOM 的界线。 Angular 也有 Shadow DOM,虽然实现手法是模拟的,但基本规则是一样的。
{Hero}from'../hero';import{HeroService}from'../hero.service';@Component({selector:'app-hero-list',template:'Heroes: {{heroes | json}}'})exportclassHeroListComponentimplementsOnInit{heroes!:Hero[];constructor(publicheroService:HeroService){}ngOnInit():void{this.heroes=this.heroService.get...
import { Component } from '@angular/core'; import { FormGroup, FormControl, Validators } from '@angular/forms'; @Component({ selector: 'app-reactive-form', templateUrl: './reactive-form.component.html', styleUrls: ['./reactive-form.component.css'] }) export class ReactiveFormComponent {...
filterSelect a subset of items from an array. jsonFormat an object to a JSON string. limitToLimits an array, or a string, into a specified number of elements/characters. lowercaseFormat a string to lower case. numberFormat a number to a string. ...
component if it is different from the previous value (based on `Object.is` equality). If code relies on the input always being set, it should be updated to copy objects or wrap primitives in order to ensure the input value differs from the previous call to `setInput`. ...
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