Using Two-Way Data Binding

Two-way data binding combines the input and output binding into a single notation using the ngModel directive.
<input [(ngModel)]="name" >
What this is doing behind the scenes is equivalent to:
<input [ngModel]="name" (ngModelChange)="name=$event">
To create your own component that supports two-way binding, you must define an @Output property to match an @Input, but suffix it with the Change. The code example below, inside class CounterComponent shows how to make property count support two-way binding.
import { Component, Input, Output, EventEmitter } from '@angular/core';
selector: 'rio-counter',
templateUrl: 'app/counter.component.html'
export class CounterComponent {
@Input() count = 0;
@Output() countChange = EventEmitter<number>();
increment() {
Count: {{ count }} -
<button (click)="increment()">Increment</button>