[html] Angular 5, HTML, boolean on checkbox is checked

Angular 5, Typescript 2.7.1

I can't seem to get the checkbox to be checked when returning a boolean, I've tried, item.check returns either true or false.

<tr class="even" *ngFor="let item of rows">
<input value="{{item.check}}" type="checkbox" checked="item.check">

The checkbox is always checked when checked is written inside input. And it does not get unchecked when checked="false".

Is there a better way to do it with Angular features instead? like ngModel or ngIf???


<input type="checkbox" [checked]="item.check == 'true'">

This question is related to html angular typescript

The answer is

Here is my answer,

In row.model.ts

export interface Row {
   otherProperty : type;
   checked : bool;
   otherProperty : type;

In .html

<tr class="even" *ngFor="let item of rows">
   <input [checked]="item.checked" type="checkbox">

In .ts

rows : Row[] = [];

update the rows in component.ts

When you have a copy of an object the [checked] attribute might not work, in that case, you can use (change) in this way:

        <input type="checkbox" [checked]="item.selected" (change)="item.selected = !item.selected">

Work with checkboxes using observables

You could even choose to use a behaviourSubject to utilize the power of observables so you can start a certain chain of reaction starting at the isChecked$ observable.

In your component.ts:

public isChecked$ = new BehaviorSubject(false);
toggleChecked() {

In your template

<input type="checkbox" [checked]="isChecked$ | async" (change)="toggleChecked()">

You can use this:

<input type="checkbox" [checked]="record.status" (change)="changeStatus(record.id,$event)">

Here, record is the model for current row and status is boolean value.

Hope this will help somebody to develop custom checkbox component with custom styles. This solution can use with forms too.


<label class="lbl">

  <input #inputEl type="checkbox" [name]="label" [(ngModel)]="isChecked" (change)="onChange(inputEl.checked)"
   *ngIf="isChecked" checked>
  <input #inputEl type="checkbox" [name]="label" [(ngModel)]="isChecked" (change)="onChange(inputEl.checked)"
   *ngIf="!isChecked" >
  <span class="chk-box {{isChecked ? 'chk':''}}"></span>
  <span class="lbl-txt" *ngIf="label" >{{label}}</span>


    import { Component, Input, EventEmitter, Output, forwardRef, HostListener } from '@angular/core';
import { ControlValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms';

const noop = () => {

  useExisting: forwardRef(() => CheckboxComponent),
  multi: true

/** Custom check box  */
  selector: 'app-checkbox',
  templateUrl: './checkbox.component.html',
  styleUrls: ['./checkbox.component.scss'],
export class CheckboxComponent implements ControlValueAccessor {

  @Input() label: string;
  @Input() isChecked = false;
  @Input() disabled = false;
  @Output() getChange = new EventEmitter();
  @Input() className: string;

  // get accessor
  get value(): any {
    return this.isChecked;

  // set accessor including call the onchange callback
  set value(value: any) {
    this.isChecked = value;

  private onTouchedCallback: () => void = noop;
  private onChangeCallback: (_: any) => void = noop;

  writeValue(value: any): void {
    if (value !== this.isChecked) {
      this.isChecked = value;

  onChange(isChecked) {
    this.value = isChecked;

  // From ControlValueAccessor interface
  registerOnChange(fn: any) {
    this.onChangeCallback = fn;

  // From ControlValueAccessor interface
  registerOnTouched(fn: any) {
    this.onTouchedCallback = fn;

  setDisabledState?(isDisabled: boolean): void {




   @import "../../../assets/scss/_variables";

.lbl {
    font-size: 12px;
    color: #282828;
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    cursor: pointer;
    &.checked {
        font-weight: 600;
    &.focus {
        border: 1px solid #a8a8a8;
          border: none;
    input {
        display: none;

    /* checkbox icon */
    .chk-box {
        display: block;
        min-width: 15px;
        min-height: 15px;
        background: url('/assets/i/checkbox-not-selected.svg');
        background-size: 15px 15px;
        margin-right: 10px;
    input:checked+.chk-box {
        background: url('/assets/i/checkbox-selected.svg');
        background-size: 15px 15px;
    .lbl-txt {
        margin-top: 0px;



Outside forms

<app-checkbox [label]="'Example'" [isChecked]="true"></app-checkbox>

Inside forms

<app-checkbox [label]="'Type 0'" formControlName="Type1"></app-checkbox>

Examples related to html

Embed ruby within URL : Middleman Blog Please help me convert this script to a simple image slider Generating a list of pages (not posts) without the index file Why there is this "clear" class before footer? Is it possible to change the content HTML5 alert messages? Getting all files in directory with ajax DevTools failed to load SourceMap: Could not load content for chrome-extension How to set width of mat-table column in angular? How to open a link in new tab using angular? ERROR Error: Uncaught (in promise), Cannot match any routes. URL Segment

Examples related to angular

error NG6002: Appears in the NgModule.imports of AppModule, but could not be resolved to an NgModule class error TS1086: An accessor cannot be declared in an ambient context in Angular 9 TS1086: An accessor cannot be declared in ambient context @angular/material/index.d.ts' is not a module Why powershell does not run Angular commands? error: This is probably not a problem with npm. There is likely additional logging output above Angular @ViewChild() error: Expected 2 arguments, but got 1 Schema validation failed with the following errors: Data path ".builders['app-shell']" should have required property 'class' Access blocked by CORS policy: Response to preflight request doesn't pass access control check origin 'http://localhost:4200' has been blocked by CORS policy in Angular7

Examples related to typescript

TS1086: An accessor cannot be declared in ambient context Element implicitly has an 'any' type because expression of type 'string' can't be used to index Angular @ViewChild() error: Expected 2 arguments, but got 1 Typescript: No index signature with a parameter of type 'string' was found on type '{ "A": string; } Understanding esModuleInterop in tsconfig file How can I solve the error 'TS2532: Object is possibly 'undefined'? Typescript: Type 'string | undefined' is not assignable to type 'string' Typescript: Type X is missing the following properties from type Y length, pop, push, concat, and 26 more. [2740] Can't perform a React state update on an unmounted component TypeScript and React - children type?