Angular 2 ngModel Not Binding Object Property Defined In Class Definition

Question

I am new to angular 2, I tried [(ngModel)] as shown below.

import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  template: `<input [(ngModel)]="model.name" name="name"> <h1>{{model.name}}</h1>`
})
export class AppComponent  { 
constructor() {
}
model = {name: "some value"};
}

The above code produces output like shown below on initial load of web page in browser..

The second one is..

import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  template: `<input [(ngModel)]="model.name" name="name"> <h1>{{model.name}}</h1>`
})
export class AppComponent  { 
constructor() {
}
model = {};
model.name = "some value";
}

This one produces following output..

Please Kindly Explain Difference Between Two Code Samples and Why It's Not Working in Second Sample..

Thanks In Advance.

Answer 1

Because you can't do assignments there. You can move the assignment into the constructor or to any other life-cycle method:

import { Component } from '@angular/core';

@Component({
  selector: 'my-app',
  template: `<input [(ngModel)]="model.name" name="name"> <h1>{{model.name}}</h1>`
})
export class AppComponent  { 
constructor() {
   this.model.name = "some value";
}
model = {};

}

Also if you look at your transpiled js file you will see something like:

function AppComponent() {
      this.model = {};
      this.name = "some value";
}