在angular 6中显示弹出警告消息几秒钟

npm install ngx-toastr

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { ToastrModule } from 'ngx-toastr';

import { AppComponent } from './app.component';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    ToastrModule.forRoot() // 添加ToastrModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

import { Component } from '@angular/core';
import { ToastrService } from 'ngx-toastr';

@Component({
  selector: 'app-root',
  template: `
    <button (click)="showWarning()">显示警告消息</button>
  `
})
export class AppComponent {
  constructor(private toastr: ToastrService) {}

  showWarning() {
    this.toastr.warning('这是一个警告消息', '警告', { timeOut: 2000 });
  }
}