Answers for "checkbox to select all checkbox angular"

checkbox to select all checkbox angular

<div style="text-align:center">
  <h1>
    {{ title }}!
  </h1>
</div>
<div class="container">
  <div class="text-center mt-5">
    <div class="row">
        <div class="col-md-6">
            <ul class="list-group">
                <li class="list-group-item">
                  <input type="checkbox" [(ngModel)]="masterSelected" name="list_name" value="m1" (change)="checkUncheckAll()"/> <strong>Select/ Unselect All</strong>
                </li>
              </ul>
              <ul class="list-group">
                <li class="list-group-item" *ngFor="let item of checklist">
                  <input type="checkbox" [(ngModel)]="item.isSelected" name="list_name" value="{{item.id}}" (change)="isAllSelected()"/>
                  {{item.value}}
                </li>
              </ul>
        </div>
        <div class="col-md-6">
            <code>{{checkedList}}</code>
        </div>
    </div>
  </div>
</div>Copy

checkbox to select all checkbox angular

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

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.scss']
})
export class AppComponent {
  title = 'Angular 7 CheckBox Select/ Unselect All';
  masterSelected:boolean;
  checklist:any;
  checkedList:any;

  constructor(){
      this.masterSelected = false;
      this.checklist = [
        {id:1,value:'Elenor Anderson',isSelected:false},
        {id:2,value:'Caden Kunze',isSelected:true},
        {id:3,value:'Ms. Hortense Zulauf',isSelected:true},
        {id:4,value:'Grady Reichert',isSelected:false},
        {id:5,value:'Dejon Olson',isSelected:false},
        {id:6,value:'Jamir Pfannerstill',isSelected:false},
        {id:7,value:'Aracely Renner DVM',isSelected:false},
        {id:8,value:'Genoveva Luettgen',isSelected:false}
      ];
      this.getCheckedItemList();
  }

  checkUncheckAll() {
    for (var i = 0; i < this.checklist.length; i++) {
      this.checklist[i].isSelected = this.masterSelected;
    }
    this.getCheckedItemList();
  }
  isAllSelected() {
    this.masterSelected = this.checklist.every(function(item:any) {
        return item.isSelected == true;
      })
    this.getCheckedItemList();
  }

  getCheckedItemList(){
    this.checkedList = [];
    for (var i = 0; i < this.checklist.length; i++) {
      if(this.checklist[i].isSelected)
      this.checkedList.push(this.checklist[i]);
    }
    this.checkedList = JSON.stringify(this.checkedList);
  }

}
Copy

select all checkbox in angular

Prepared a small demo to show how this can be done using ngModel directive. Link: https://stackblitz.com/edit/angular-lxjrdh

It uses Array.every to check if all are checked or not. If checked, it resets all otherwise checks all.