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up vote 17 down vote favorite
1

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?

share|improve this question
    
ES6?​​​​​​​​​​​ – Cerbrus Nov 6 '15 at 7:49
    
This is written in Typescript – Yaniv Efraim Nov 6 '15 at 7:50
    
Right. Adding that tag. – Cerbrus Nov 6 '15 at 7:51
up vote 44 down vote accepted

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
  }
}
share|improve this answer
    
Thanks! This is exactly what I needed – Yaniv Efraim Nov 6 '15 at 8:42
4  
@YanivEfraim I have updated my answer, please check it out. And this api is likely to change in future. github.com/angular/angular/issues/5036 – Herrington Darkholme Nov 6 '15 at 9:15
    
Based on the newer api, you actually need to import OnInit from "angular2/angular2", and then change your class to implement OnInit so it should look like: export default class NamesComponent implements OnInit { ... } – jgo Dec 4 '15 at 22:37
1  
This answer is no longer relevant, however I can't edit the answer due to SO's far too aggressive limitations. You need to now use ngOnInit instead of onInit. – lux Dec 21 '15 at 20:38
1  
@lux I have updated – Herrington Darkholme Dec 23 '15 at 2:55

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