import { Component, OnInit, Input, OnChanges, SimpleChanges } from '@angular/core';@Component({  selector: 'app-child',  templateUrl: './child.component.html',  styleUrls: ['./child.component.css']})export class ChildComponent implements OnInit, OnChanges {  @Input()  greeting: string;  @Input()  user: {};  message = 'hello';  constructor() { }  ngOnInit() {  }  ngOnChanges(changes: SimpleChanges): void {    console.log(JSON.stringify(changes, null, 2));  }}

     
      子组件
     
问候语{
   {greeting}}
用户{
   {user.name}}

import { Component } from '@angular/core';@Component({  selector: 'app-root',  templateUrl: './app.component.html',  styleUrls: ['./app.component.css']})export class AppComponent {  greeting = 'nihao';  user: { name: string } = { name: 'cys' };}