效果圖

程式碼：

        <div class="form-group">
          <div class="input-group">
            <input type="text" class="form-control" placeholder="Recipient's username">
            <span class="input-group-addon" [ngClass]="{'fa': true, 'fa-eye': pwdShow, 'fa-eye-slash': !pwdShow}"
              (click)="pwdShow = !pwdShow" style="cursor: pointer;"></span>
          </div>
        </div>
 

ts裡定義一個

pwdShow: false;