Pass enums in angular2 view templates

Question

Can we use enums in an angular2 view template?

<div class="Dropdown" dropdownType="instrument"></div>

passes the string as input:

enum DropdownType {
    instrument,
    account,
    currency
}

@Component({
    selector: '[.Dropdown]',
})
export class Dropdown {

    @Input() public set dropdownType(value: any) {

        console.log(value);
    };
}

But how to pass an enum configuration? I want something like this in the template:

<div class="Dropdown" dropdownType="DropdownType.instrument"></div>

What would be the best practice?

Edited: Created an example:

import {bootstrap} from 'angular2/platform/browser';
import {Component, View, Input} from 'angular2/core';

export enum DropdownType {

    instrument = 0,
    account = 1,
    currency = 2
}

@Component({selector: '[.Dropdown]',})
@View({template: ''})
export class Dropdown {

    public dropdownTypes = DropdownType;

    @Input() public set dropdownType(value: any) {console.log(`-- dropdownType: ${value}`);};
    constructor() {console.log('-- Dropdown ready --');}
}

@Component({ selector: 'header' })
@View({ template: '<div class="Dropdown" dropdownType="dropdownTypes.instrument"> </div>', directives: [Dropdown] })
class Header {}

@Component({ selector: 'my-app' })
@View({ template: '<header></header>', directives: [Header] })
class Tester {}

bootstrap(Tester);

Answer 1

Create a property for your enum on the parent component to your component class and assign the enum to it, then reference that property in your template.

export class Parent {
    public dropdownTypes = DropdownType;        
}

export class Dropdown {       
    @Input() public set dropdownType(value: any) {
        console.log(value);
    };
}

This allows you to enumerate the enum as expected in your template.

<div class="Dropdown" [dropdownType]="dropdownTypes.instrument"></div>

Answer 2

Create an Enum:

enum ACTIVE_OPTIONS {
  HOME = 0,
  USERS = 1,
  PLAYERS = 2
}

Create a component, be sure your enum list will have the typeof:

export class AppComponent {
  ACTIVE_OPTIONS = ACTIVE_OPTIONS;
  active: ACTIVE_OPTIONS;
}

Create a template:

<li [ngClass]="{ 'active': active === ACTIVE_OPTIONS.HOME }">
  <a routerLink="/in">
    <i class="fa fa-fw fa-dashboard"></i> Home
  </a>
</li>

Answer 3

If you want get Enum name :

export enum Gender {
       Man = 1,
       Woman = 2
   }

then in component file

public gender: typeof Gender = Gender;

in template

<input [value]="gender.Man" />

Answer 4

Maybe you don't have to do this.

For example, in Numeric Enum:

export enum DropdownType {
    instrument = 0,
    account = 1,
    currency = 2
}

In HTML Template:

<div class="Dropdown" [dropdownType]="1"></div>

result: dropdownType == DropdownType.account

or String Enum:

export enum DropdownType {
    instrument = "instrument",
    account = "account",
    currency = "currency"
}

<div class="Dropdown" [dropdownType]="'currency'"></div>

result: dropdownType == DropdownType.currency

---

If you want get Enum name :

val enumValue = DropdownType.currency
DropdownType[enumValue] //  print "currency", Even the "numeric enum" is also.