Troubleshooting issue of data-binding failure with dynamic component loader in Angular2-universal-started

I am currently utilizing the angular2-universal-starter project.

While attempting to pass an object to a child component using @Input, I encountered some issues with it not functioning correctly.

I have implemented a dynamic component loader to load the child component and had the intention of passing the object to it.

Below is a snippet of my code:

app.component.ts

import {Component, Directive, Renderer, DynamicComponentLoader, ElementRef} from 'angular2/core';
import {Http} from 'angular2/http';    
import {headingComponent} from './heading.component';

@Directive({
  selector: '[x-large]'
})
export class XLarge {
  constructor(element: ElementRef, renderer: Renderer) {
    renderer.setElementStyle(element.nativeElement, 'fontSize', 'x-large');
  }
}

// App component definition

@Component({
  selector: 'app',
  directives: [    
    XLarge
  ],  
  template: `
    <div>
        <div>
        <span x-large>Hello, {{ user.name }}!</span>
        </div>
        <icici-heading [user]="user"></icici-heading>      
    </div>
`
})
export class App {
  public user;       
  
  // Constructor method 

  constructor(dcl: DynamicComponentLoader, elementRef: ElementRef) {          
      dcl.loadNextToLocation(headingComponent, elementRef);
  }
  
  ngOnInit(){
      this.user = { "id": 11, "name": "Mr. Nice" };
  }  
}

heading.component.ts

import {Component, OnInit, Input} from 'angular2/core';

@Component({
    selector: 'icici-heading',
    template: `
        <div>
        <!--{{user.name}}-->this is not working
        {{name}}
       </div>
`   
 })

export class headingComponent implements OnInit {
    @Input() user;
    name: string;

    constructor() { }

    ngOnInit() { 
        this.name="heading is rendered";
    }    
}

Answer №1

To improve your code, consider adding more flexibility for when the value is not yet available.

Here is a solution:

{{user?.name}}

The use of the Elvis or safe-navigation operator ensures that .name is evaluated only when user != null

When it comes to dynamically added components, values may need to be passed imperatively as well

dcl.loadNextToLocation(headingComponent, elementRef)
.then(cmpRef => cmpRef.instance.user = this.user);

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