Angular ng Bootstrap Collapse Component

Last Updated : 06 Jul, 2021

Angular ng bootstrap is a bootstrap framework used with angular to create components with great styling and this framework is very easy to use and is used to make responsive websites.

In this article we will know how to use Collapse in angular ng bootstrap. Collapse is used to make a button that will be collapsed by clicking on it.

Installation syntax:

ng add @ng-bootstrap/ng-bootstrap

Approach:

First, install the angular ng bootstrap using the above-mentioned command.

Import ng bootstrap module in module.ts

import { NgbModule } from '@ng-bootstrap/ng-bootstrap';

imports: [
  NgbModule
]

In app.component.html make a collapse component.
Serve the app using ng serve.

Example 1: In this example, we are making a basic collapse component.

app.component.html

<p>
  <br/>
  <button type="button"
          class="btn btn-success" 
          (click)="collapse.toggle()" 
          [attr.aria-expanded]="!gfg"
    aria-controls="collapseExample">
    Click to collapse
  </button>
</p>

<div #collapse="ngbCollapse" 
     [(ngbCollapse)]="gfg">
  <div class="card">
    <div class="card-body">
      Angular10 ng bootstrap
    </div>
  </div>
</div>

app.module.ts

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

// Importing forms module
import { FormsModule, ReactiveFormsModule  }
from '@angular/forms';
import { BrowserModule } 
from '@angular/platform-browser';
import { BrowserAnimationsModule } 
from '@angular/platform-browser/animations';
 
import { AppComponent }  
from './app.component';
import { NgbModule }
from '@ng-bootstrap/ng-bootstrap';
 
@NgModule({
  bootstrap: [
    AppComponent
  ],
  declarations: [
    AppComponent
  ],
  imports: [
    FormsModule,
    BrowserModule,
    BrowserAnimationsModule,
    ReactiveFormsModule,
    NgbModule
  ]
})
export class AppModule { }

app.component.ts

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

@Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
})
export class AppComponent {
    public gfg = false;
}

Output:

Example 2: In this example, we have pre collapsed the component.

app.component.html

<p>
  <br/>
  <button type="button"
          class="btn btn-success"
          (click)="collapse.toggle()"
          [attr.aria-expanded]="!gfg"
    aria-controls="collapseExample">
    Click to collapse
  </button>
</p>

<div #collapse="ngbCollapse"
     [(ngbCollapse)]="gfg">
  <div class="card">
    <div class="card-body">
      Angular10 ng bootstrap
    </div>
  </div>
</div>

app.module.ts

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

// Importing forms module
import { FormsModule, ReactiveFormsModule  }
from '@angular/forms';
import { BrowserModule }
from '@angular/platform-browser';
import { BrowserAnimationsModule }
from '@angular/platform-browser/animations';

import { AppComponent }  
from './app.component';
import { NgbModule } 
from '@ng-bootstrap/ng-bootstrap';
 
@NgModule({
  bootstrap: [
    AppComponent
  ],
  declarations: [
    AppComponent
  ],
  imports: [
    FormsModule,
    BrowserModule,
    BrowserAnimationsModule,
    ReactiveFormsModule,
    NgbModule
  ]
})
export class AppModule { }

app.component.ts

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

@Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
})
export class AppComponent {
    public gfg = true;
}