NetanelBasal

 validateUniqueEmailObservable( email : string ) {
    return new Observable(observer => {
      if( email === "alreadyExistsEmail@gmail.com" ) {
        observer.next({asyncInvalid: true});
      } else {
        observer.next(null);
      }
    });
  }

NetanelBasal

validate( c : AbstractControl )  {
    return this.validateUniqueEmailObservable(c.value);
}

NetanelBasal

validate( c : AbstractControl )  {
    return this.validateUniqueEmailObservable(c.value).first();
}

NetanelBasal

validate( c : AbstractControl )  {
  return this.validateUniqueEmailObservable(c.value).debounceTime(500).distinctUntilChange().first();
}

NetanelBasal

import { Component } from '@angular/core';
import { ViewChild } from "@angular/core/src/metadata/di";

@Component({
  selector: 'app-root',
  templateUrl: '<input type="text" #input>'
})
export class AppComponent {
  @ViewChild("input") input;
  

NetanelBasal

import { Directive, Renderer, ElementRef } from '@angular/core';
@Directive({
  selector: '[exploreRenderer]'
})
export class ExploreRendererDirective {
  private nativeElement : Node;
  constructor( private renderer : Renderer, private element : ElementRef ) {
    this.nativeElement = element.nativeElement;
  }
}

NetanelBasal

ngAfterContentInit() {
  let inputElement = this.renderer.createElement(this.nativeElement, "input");
  this.renderer.setElementAttribute(inputElement, "value", "Hello from renderer");
  this.renderer.invokeElementMethod(inputElement, "focus", []);
}

NetanelBasal

ngAfterContentInit() {
    let buttonElement = this.renderer.createElement(this.nativeElement, "button");
    this.renderer.createText(buttonElement, "Click me!");
    this.renderer.setElementProperty(buttonElement, "disabled", true);
    this.renderer.listen(buttonElement, "click", ( event ) => console.log(event));
    this.renderer.setElementClass(buttonElement, "btn-large", true);
    this.renderer.setElementStyle(buttonElement, "backgroundColor", "yellow");
}

NetanelBasal

let input = document.querySelector('input[type="text"]');
let button = document.querySelector('button');
let h1 = document.querySelector('h1');

button.addEventListener('click', () => {
  emitter.emit('event:name-changed', {name: input.value});
});

let emitter = new EventEmitter();
emitter.subscribe('event:name-changed', data => {

NetanelBasal

class EventEmitter {
  constructor() {
    this.events = {};
  }
}