Implement two-way data binding for custom property

Question

I see in primeng components the use something like ngModel (two-way data binding) style for some property like this

[(selection)]="selectedItem";

it 's look like

@Input() selection;
@Output() selection:EventEmitter<any> = new EventEmitter<any>();

how I can implement something like this and is it possible to do for more than single property like

 <component-a  [(selection)]="selectedItem"  [(data)]="selectedData"></component-a>

Answer 1

Angular docs

<app-sizer 
  [(size)]="fontSizePx">
</app-sizer>

The two-way binding syntax is really just syntactic sugar for a property binding and an event binding. Angular desugars the binding into this:

<app-sizer
  [size]="fontSizePx"
  (sizeChange)="fontSizePx=$event">
</app-sizer>

To create two-way binding for property selection use:

@Input() selection;

// You have to follow this convention (For Output property)
// i.e. <propertyName><Change> like selectionChange

@Output() selectionChange:EventEmitter<any> = new EventEmitter<any>();

And to change selection in component as shown below:

changeSelection(newSelection)
{
    this.selection = newSelection;

    // emit change event to parent component
    this.selectionChange.emit(this.selection);  
}