How hide and show in angular 4.0

Question

I am trying to toggle menu in angular 4. I have 2 separate components. One is for header layout and second one is for menu list. I have written toggle function on click of icon in the header layout and I am trying to hide and show the menu list. But this is not working for me.

Following are my code:

app.navbarComponent.html file:

<header id='sv_header'>
  <div class='row'>
    <div class='col-lg-4 col-md-4 col-sm-4 col-xs-4 col'>
      <a href='' class='logo'>
        <img src='{{ logo }}' alt='Savaari' />
      </a>
    </div>
    <div class='col-lg-4 col-md-4 col-sm-4 col-xs-4 col supportHolder'>
        <img src='{{ customercare }}' alt='24X7 Customer Care Support' />
    </div>
    <div class='col-lg-4 col-md-4 col-sm-4 col-xs-4 text-right col loginHolder'>
      <a class='user_login' (click)='toggleMenu()'>
        <img src='{{ signin }} ' alt='signin' />
        <span>Sign In</span>
      </a>
    </div>
  </div>
</header>

app.navbarComponent.ts file:

import { Component } from '@angular/core';
@Component({
    selector: 'navbar',
    templateUrl: './app.navbarComponent.html'
})
export class NavbarComponent {
    menulist: boolean = false;
    logo = '../assets/img/logo.png';
    customercare = '../assets/img/cc-support.png';
    signin = '../assets/img/signin.png';
    toggleMenu(): void { 
        this.menulist = !this.menulist;
        alert(this.menulist);
    }
}

app.menuComponent.html file:

<div class='menulist'  >
  <ul>
    <li *ngFor="let menu of menus" [HIDDEN]="!menulist">
      <a href="{{menu.href}}">
        {{menu.name}}
      </a>
    </li>
  </ul>
</div>

Can anyone help me to resolve this.

Thanks in advance.

Answer 1

<div class='menulist'>
  <ul *ngIf="!menulist">
    <li *ngFor="let menu of menus">
      <a href="{{menu.href}}">
        {{menu.name}}
      </a>
    </li>
  </ul>
</div>

You can't put *ngIf and *ngFor on the same element - angular does not like it

Answer 2

It seems to me the right answer is not correct. Angular has two ways to hide data: *ngIf and [hidden].
*ngIf is a structural directive, it creates/destroys content inside the DOM.
[hidden] just hides/shows the content with css (adding/removing display:none to the element's style).
*ngIf redraws DOM, which affects the performance of your project. In this case I advise to use [hidden], because you often manipulate the DOM