use ngif in angular 8 code example

Example 1: ngIf else

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>

Example 2: ngif

@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;
}