<li *ngIf='condition'></li>

import { Component, Inject } from '@angular/core';
import { PLATFORM_ID } from '@angular/core';
import { isPlatformWorkerApp } from '@angular/common';
  
@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
  
  export class AppComponent  {
    myBool = true;
  }

<div *ngIf = 'myBool'>Boolean is set to true</div>

import { Component, Inject } from '@angular/core';
import { PLATFORM_ID } from '@angular/core';
import { isPlatformWorkerApp } from '@angular/common';
  
@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  variab = 10;
}

<div *ngIf = 'variab==1; else multi'>{{variab}}</div>
  
<ng-template #multi>
    {{variab *2}}
  </ng-template>