How to change Icon of collapse and expand?

Question

My code is below and I want to change icon up and down when collapse and expand is done. But somehow it's not working.

<div class="attach-link">

                <a href="javascript:void(0);" *ngIf="fileData.fileDataType.canAttach && !isFinancialEntity" (click)="openFileInput(i)">
                    <i class="fa fa-plus"></i> Add Attachment</a>
                <input type="file" class="hide" id="fileData_{{i}}" ng2FileSelect [uploader]="fileData.uploader" (onFileSelected)="onFileSelected()"
                />
                <a class="attachFileList" href="#attachFileList_{{i}}" data-toggle="collapse">
                    <i class="fa fa-angle-up" ></i>                       

                    Attachments [{{fileData.fileList.length}}] </a>
            </div>

And added script :

 $('a[data-toggle="collapse"]').click(function () {            
        //$(this).find('i').addClass('fa fa-angle-up').removeClass('fa fa-angle-down');
        $(this).find('i .fa fa-angle-up').toggleClass('fa fa-angle-down');
    });

I don't know what is the problem. Any help will be appreciated. Many Thanks.

Answer 1

Here is the sample code of collapse up and down in angular.

<div class="attach-link">
      <a href="javascript:void(0);"  (click)="openFileInput(i)">
              <i class="fa fa-plus"></i> Add Attachment</a>
            <input type="file" class="hide" id="fileData_{{i}}" ng2FileSelect (onFileSelected)="onFileSelected()"
            />
             <br>                
            <a (click)="collapse=!collapse" class="attachFileList" href="#attachFileList_{{i}}" data-toggle="collapse">
                <i class="fa" [ngClass]="{'fa-angle-up': collapse, 'fa-angle-down': !collapse}"></i>    
                Attachments {{fileData.fileList.length}}                 
            </a>
 </div>

Controller

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

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  name = 'Angular 5';
  collapse:boolean =true;
}