What would be a good use for NgZone Service?

Angular 2 runs inside of its own special zone called NgZone and this special zone extends the basic functionality of a zone to facilitate change detection.

It is Running inside a zone allows to detect when asynchronous tasks.

If you change or update your internal application code or view and it is detecting the applications changes with help of NgZone.

Example 1 - We use NgZone to trigger change detection as

import { Component, NgZone} from '@angular/core';
import { CommonModule } from '@angular/common';
import { HttpModule, Http } from '@angular/http';
import { UserService } from '../service/user.service';
import { AppGlobals } from '../../shared/app.globals';


@Component({
    selector: 'user',
    templateUrl: './user.component.html',
    styleUrls: ['./user.component.css'],
    providers: [UserService, AppGlobals]
})

export class UserComponent {
    //USERS DECLARATIONS.
    users = [];
    label: string;
    counter: number = 0;

    //USER COMPONENT CONSTRUCTOR.
    constructor(private _userService: UserService,
        private _global: AppGlobals,
        private _ngZone: NgZone)
    { }

    //GET USERS SERVICE ON PAGE LOAD and BIND UI GRID.
    ngOnInit() {
        this._userService.getAPIUsers(this._global.baseAPIUrl + 'users/hadley/orgs').subscribe(data => this.users = data);
        this._userService.getAppUsers(this._global.baseAppUrl + 'api/User/GetUsers').subscribe(data => console.log(data));   
    }

    // Loop inside the Angular zone. 
    // The UI will refresh after each setTimeout cycle.
    insideOfAngularZone() {
        this.label = 'inside loop';
        this.counter = 0;
        this._increaseCounter(() => alert('Inside loop completed.'));
    }

    // Loop outside of the Angular zone. 
    // The UI will not refresh after each setTimeout cycle.
    outsideOfAngularZone() {
        this.label = 'outside loop';
        this.counter = 0;
        this._ngZone.runOutsideAngular(() => {
            this._increaseCounter(() => {
                this._ngZone.run(() => {
                    alert('Outside loop completed.');
                });
            });
        });
    }

    _increaseCounter(doCallback: () => void) {
        this.counter += 2;

        if (this.counter <= 1000) {
            window.setTimeout(() => {
                this._increaseCounter(doCallback);
            }, 100);
        }
        else {
            doCallback();
        }
    }  
}
//END BEGIN - USER-COMPONENT

Example 2 -We use NgZone to trigger change detection as,

constructor(_ngZone:NgZone) {
    window.onresize = (e) =>
    {
        _ngZone.run(() => {
            this.width = window.innerWidth;
            this.height = window.innerHeight;
        });
    };
}

import {ChangeDetectorRef} from '@angular2/core'

export class SideNav {
    innerWidth: number;

    constructor(private window: Window, private _cdr: ChangeDetectorRef){

       let getWindow = () => {
          return window.innerWidth;
       };

      window.onresize = () => {
          this.innerWidth = getWindow();
          this._cdr.detectChanges(); //running change detection manually!
      };
    }
}

I hope you are enjoying with this post! Please share with you friends. Thank you!!

Pin it

Anil Singh is an author, tech blogger, and software programmer. Book writing, tech blogging is something do extra and Anil love doing it. For more detail, kindly refer to this link..

My Tech Blog - https://www.code-sample.com/
My Books - Book 1 and Book 2