Angular自定义键盘事件节流指令

最新推荐文章于 2024-02-19 20:30:00 发布

原创最新推荐文章于 2024-02-19 20:30:00 发布 · 575 阅读

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本文介绍了如何在Angular中创建一个自定义指令，用于处理键盘事件并实现节流效果。通过阅读，你可以了解到具体的创建步骤以及相关代码示例。

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1、创建指令

// 以下命令会创建DebounceDirective指令并自动添加到AppModule
ng g directive directive/debounce

2、相关代码

// app.component.html

<input appDebounce [debounceTime]='2000' (debounceKeyup)="testDebounceKeyup($event)" />

// app.component.ts

import { Component } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.styl']
})

export class AppComponent {

  testDebounceKeyup(event: any) {
    console.log("Keyup被节流了！");
  }
  
}

// debounce.directive.ts

import { Directive, EventEmitter, HostListener, Input, Output, OnInit, OnDestroy } from '@angular/core';
import { debounceTime } from 'rxjs/operators';
import { Subject, Subscription } from 'rxjs/';

@Directive({
  selector: '[appDebounce]'
})

export class DebounceDirective implements OnInit, OnDestroy {

  private operates = new Subject<any>();
  @Input()
  private debounceTime = 1000;
  @Output()
  private debounceKeyup = new EventEmitter();
  private keyupScription: Subscription;

  constructor() { }

  ngOnInit() {
    this.keyupScription = this.operates
      .pipe(debounceTime(this.debounceTime))
      .subscribe(e => this.debounceKeyup.emit(e));
  }

  @HostListener('keyup', ['$event'])
  keyupEvent(event: KeyboardEvent) {
    event.preventDefault();
    event.stopPropagation();
    this.operates.next(event);
    console.log("我被输入了！");
  }

  ngOnDestroy() {
    this.keyupScription.unsubscribe();
  }
  
}