Yaniv Efraim Yaniv Efraim - 4 months ago 10
Javascript Question

Angular2 - cannot access "Inputs" from my controller/constructor

I have a simple Angular 2 component with

@Input
, which I bind to the template. The template shows input data, but I cannot access it from the constructor:

import {Component, View, bootstrap, Input} from 'angular2/angular2';
import DataService from './data-service';

@Component({
selector: 'app-cmp'
})
@View({
template: `{{data.firstName}} {{data.lastName}}` //-> shows the correct 'data'
})
export default class NamesComponent {
@Input() data: any;
constructor(dataService: DataService) {
console.log(this.data);//undefined
}
}


Here is a plunker with an example (see "names-component.ts").

What am I doing wrong?

Answer

Because the Input property isn't initialized until view is set up. According to the doc, you can access your data in onInit method.

import {Component, bootstrap, Input} from '@angular/core';
import DataService from './data-service';

@Component({
    selector: 'app-cmp',
    template: `{{data.firstName}} {{data.lastName}} {{name}}`
})
export default class NamesComponent {
  @Input() data;
  name: string;
  constructor(dataService: DataService) {
    this.name = dataService.concatNames("a", "b");
    console.log(this.data); // undefined here
  }
  ngOnInit() {
    console.log(this.data); // object here
  }
}