Custom Input and Output on Same Name in Angular2 2 Way Binding

Question

I know how to fix my component using a different name for the output value of this component.

let me share my code

import {Component, Input, Output, EventEmitter} from '@angular/core'; import {TranslationPipe} from "../pipes/translation.pipe";

@Component({
  selector: 'msisdn-confirm',
  template: `
  <div class="msisdn-confirm">
    <div>
      <input type="text" [(ngModel)]="m1">
    </div>
    <div>
      <input type="text" [(ngModel)]="m2">
    </div>
    <p class="error">{{message}}</p>
  </div>
`
})
export class MsisdnConfirm {
  message:string;
  @Output('mobile') emitter: EventEmitter<string> = new EventEmitter<string>();
  @Input('mobile') set setMobileValue(value) {
    this.msisdn_confirm = this.msisdn = value;
  }

  set m1(value) {
    this.msisdn = value;
    if (this.valid()) {
      console.log('emit' + this.msisdn);
      this.emitter.emit(this.msisdn);
    }
  }

  set m2(value) {
    this.msisdn_confirm = value;
    if (this.valid()) {
      console.log('emit' + this.msisdn);
      this.emitter.emit(this.msisdn);
    }
  }

  get m1():string {
    return this.msisdn;
  }
  get m2():string {
    return this.msisdn_confirm
  }

  msisdn: string;
  msisdn_confirm: string;

  constructor() {

  }

  private valid(): boolean {
    if (!/06[0-9]{8}/.test(this.msisdn)) {
      this.message = new TranslationPipe().transform("Het mobiele nummer is incorrect, (bijvoorbeeld: 0612345678)")
      return false;
    } else if (this.msisdn != this.msisdn_confirm) {
      this.message = new TranslationPipe().transform("De mobiele nummers komen niet overeen")
      return false;
    }
    this.message = null;
    return true;
  }
}

So this is a very basic component which validates two strings to be a "valid" dutch Mobile number, so a confirm box so to say. Now I can get my value in the parent component by doing something like

(mobile)="myParam = $event"

What I want is to use it like

[(mobile)]="myParam"

This only works for setting though, is this not supported on custom components?

Accepted Answer

For this compact syntax to work the input and output need to follow specific naming rules

[(mobile)]="myParam"

  @Output('mobileChange') emitter: EventEmitter<string> = new EventEmitter<string>();
  @Input('mobile') set setMobileValue(value) {
    this.msisdn_confirm = this.msisdn = value;
  }

Renaming inputs and outputs by passing a string parameter to the decorator is discourages. Rather use

  @Output() mobileChange: EventEmitter<string> = new EventEmitter<string>();
  @Input() set mobile(value) {
    this.msisdn_confirm = this.msisdn = value;
  }

Answer 2

Another example of Gunter's code above that may help:

export class TaskBook {
  public taskBookID: number;
  public title: String; 
}

Inside component code:

   ....
    <input type="text"  pInputText [(ngModel)]="data!.title" (change)="onDataChange()" />
   ....

 @Component({
  selector: 'taskbook_edit',
  templateUrl: './taskbook_edit.component.html' 
})
    export class TaskbookEditComponent { 

      @Input() data: TaskBook;
      @Output() dataChange = new EventEmitter<TaskBook>();

      constructor() { } 

      onDataChange() { 
        this.dataChange.emit(this.data);
      }  
    }

Outside in calling component:

<taskbook_edit  [(data)]="taskbookObj" ></taskbook_edit>

 public taskbookObj: TaskBook;

Custom Input and Output on Same Name in Angular2 2 Way Binding

2 Answers

Must Read

Your Answer

Robert Thorne

Custom Input and Output on Same Name in Angular2 2 Way Binding

2 Answers

Must Read

Your Answer

Sign up or log in

Post as a guest

Robert Thorne