angular - 在 TypeScript/Angular 4+ 中将枚举键显示为字符串

Question

export enum Type {
    TYPE_1 : "Apple",
    TYPE_2 : "Orange",
    TYPE_3 : "Banana"
}

当我记录 Type.TYPE_1 时，默认调用 toString 方法。

console.log(Type.TYPE_1 + " is " + Type.TYPE_1.toString());

Output => Apple is Apple

我的期望是结果是这样的

Output : TYPE_1 is Apple

如何将 key TYPE_1 记录/获取为字符串？

有没有办法像下面那样做 override method？

export enum Type {
    TYPE_1 : "Apple",
    TYPE_2 : "Orange",
    TYPE_3 : "Banana"

    toString() {
        this.key + " is " + this.toString();
        <or>
        this.key + " is " + this.value();
    }
}

我已经用谷歌搜索了，我还不行。

更新

目的是在UI中展示

export enum Currency {
    USD : "US Dollar",
    MYR : "Malaysian Ringgit",
    SGD : "Singapore Dollar",
    INR : "Indian Rupee",
    JPY : "Japanese Yen"
}

currencyList : Currency[]= [Currency.USD, Currency.MYR, Currency.SGD, Currency.INR, Currency.JPY];

<table>
    <tr *ngFor="let currency of currencyList">
        <td>
            <input name="radioGroup" type="radio" [(ngModel)]="selectedType" [value]="currency">

            <label>{{currency}} is {{currency.toString()}}</label>    
            <!--
                here expectiation is Example 
                    USD is US Dollar
                    MYR is Malaysian Ringgit
                    SGD is Singapore Dollar
                    ....

                Now I get "US Dollar is US Dollar"....
            -->             
        </td>
    </tr>
</table>

Answer 1

您可以像下面那样使用keyvalue 管道，工作示例在Stackblitz 中并且您的 enum 语法错误...请检查 Enums

注意:下面是Angular 6

请查看Angular 6.1 introduces a new KeyValue Pipe

types.ts 代码

export enum Type {
  USD = "US Dollar",
  MYR = "Malaysian Ringgit",
  SGD = "Singapore Dollar",
  INR = "Indian Rupee",
  JPY = "Japanese Yen"
}

Component.ts 代码

import { Component } from '@angular/core';
import { Type } from './types';

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

export class AppComponent  {
  name = 'Angular';
  states = Type;
}

Component.template代码

<table>
    <tr *ngFor="let state of states | keyvalue">
        <td>
            <input name="radioGroup" type="radio" [(ngModel)]="selectedType" [value]="currency">
            <label>{{state.key + " is " + state.value}}</label>             
        </td>
    </tr>
</table>

更新:

对于 Angular < 6，请检查 stackoverflow 之一 question