angular 2 input decorator why it need?

Question

I study Angular 2.I was faced with the task to transfer the data to the component of parent component.in Official documentation is written to use the @ input.No but I do not understand why the developers of angular 2 made it need?.Why would not have made a transfer without @ INPUT.Why add @Input?In documentation in explain it is not clear for me

Answer 1

To define an input for a component, use the @Input decorator.

For example component needs a user argument to render information about that user:

<user-profile [user]="currentUser"></user-profile>

So, you need to add an @Input binding to user:

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

@Component({
  selector: 'user-profile',
  template: '<div>{{user.name}}</div>'
})
export class UserProfile {
  @Input() user;
  constructor() {}
}

Answer 2

Bindings in components template like [inputProp]="someValue" are only allowed for @Input() inputProp; or native properties of HTML elements with matching names.

I'm only guessing but 2 explanations come to my mind

• more efficient code or code generation If properties need to be made explicit, this allows more efficient code

• better support for tools This allows tools to check for errors in your code, provide autocompletion when writing templates, and probably more