ngif

<div *ngIf="isLoggedIn; else loggedOut">
  Welcome back, friend.
</div>

<ng-template #loggedOut>
  Please friend, login.
</ng-template>

<div *ngIf="condition; else elseBlock">Content to render when condition is true.</div>
<ng-template #elseBlock>Content to render when condition is false.</ng-template>

      
        content_copy
      
      <div *ngIf="condition; then thenBlock else elseBlock"></div>
<ng-template #thenBlock>Content to render when condition is true.</ng-template>
<ng-template #elseBlock>Content to render when condition is false.</ng-template>
    

<ng-container
  *ngIf="isLoggedIn; then loggedIn; else loggedOut">
</ng-container>

<ng-template #loggedIn>
  <div>
    Welcome back, friend.
  </div>
</ng-template>
<ng-template #loggedOut>
  <div>
    Please friend, login.
  </div>
</ng-template>

    <div *ngIf="condition; else elseBlock">
         
<button class="xx" *ngIf="flag" (click)="doFunct()">Next</button>
   
--While (t/f boolean variable called "flag") is true
  This button will be visible + click button executes function
  Once this "flag" becomes false this button disapears

<div *ngIf="condition">

<label>Click me: <input type="checkbox" ng-model="checked" ng-init="checked=true" /></label><br/>
Show when checked:
<span ng-if="checked" class="animate-if">
  This is removed when the checkbox is unchecked.
</span>