Angular 在typescript中初始化并赋值

我有一个组件，我在其中传递输入值preferredContactMethods

我想初始化另一个变量alternateContactMethods，并指定与preferredContactMethods相同的值

我试过：

Object.assign

直接分配

什么都不管用

任何建议或示例都会很有帮助。

Angular为您提供了一个解决方案。这将使您有机会仅在输入更改时设置值。它将如下所示：

You need to do following to assign value:

import { Component, Input, OnInit } from '@angular/core';

export class YourComponent implements OnInit {

   @Input() preferredContactMethods: Array<string>;
   public alternateContactMethods: Array<string>

   ngOnInit(): void {
      console.log(this.preferredContactMethods);  // To check value is exist or not.
      this.alternateContactMethods = [...this.preferredContactMethods];. // Assign the copy of preferredContactMethods array
   }

}

private _preferredContactMethods: Array<string>;
private _alternateContactMethods: Array<string>;

// Here you can set/compare/calculate/... when your input changes
@Input() set preferredContactMethods(args: Array<string>){
  this._preferredContactMethods = args;
  this._alternateContactMethods = args;
};

---

这只在组件初始化后工作一次。这只在组件初始化后工作一次。

You need to do following to assign value:

import { Component, Input, OnInit } from '@angular/core';

export class YourComponent implements OnInit {

   @Input() preferredContactMethods: Array<string>;
   public alternateContactMethods: Array<string>

   ngOnInit(): void {
      console.log(this.preferredContactMethods);  // To check value is exist or not.
      this.alternateContactMethods = [...this.preferredContactMethods];. // Assign the copy of preferredContactMethods array
   }

}

 Patent component html file like this:
<Your-Component  [preferredContactMethods]="data" ></Your-Component>

Child Component.ts file   
import { Component, Input, OnInit } from '@angular/core';

export class YourComponent implements OnInit {

   @Input() preferredContactMethods: Array<string>;
   alternateContactMethods: Array<string>

   ngOnInit(): void {
      console.log(this.preferredContactMethods);  // To check value is exist or not.
      this.alternateContactMethods = this.preferredContactMethods;
   }

}

private _preferredContactMethods: Array<string>;
private _alternateContactMethods: Array<string>;

// Here you can set/compare/calculate/... when your input changes
@Input() set preferredContactMethods(args: Array<string>){
  this._preferredContactMethods = args;
  this._alternateContactMethods = args;
};