Check out example codes for "ngif". It will help you in understanding the concepts better.

Code Example 1

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

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

Code Example 2

<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

Code Example 3

<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>

Code Example 4

<div *ngIf="condition">

Code Example 5

<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>

Code Example 6

@Component({
  selector: 'ng-if-else',
  template: `
    <button (click)="show = !show">{{show ? 'hide' : 'show'}}</button>
    show = {{show}}
    <br>
    <div *ngIf="show; else elseBlock">Text to show</div>
    <ng-template #elseBlock>Alternate text while primary text is hidden</ng-template>
`
})
export class NgIfElse {
  show: boolean = true;
}

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