In Angular document, * and template, we know that the *ngIf, *ngSwitch, *ngFor can be expanded to ng-template tag. My question is:
I think the
* can also be translated and expanded to template tag by Angular engine.
The following code
<hero-detail *ngIf="currentHero" [hero]="currentHero"></hero-detail>
would be the same as
<ng-template [ngIf]="currentHero"> <hero-detail [hero]="currentHero"></hero-detail> </ng-template>
So why bother designing a strange symbol asterisk(
*) in Angular?
Asterisk syntax is a syntatic sugar for more wordy template syntax which directive expands to under the hood, you are free to use any of these options.
Quote from the docs:
The asterisk is “syntactic sugar”. It simplifies ngIf and ngFor for both the writer and the reader. Under the hood, Angular replaces the asterisk version with a more verbose form.
The next two ngIf examples are effectively the same and we may write in either style:<!-- Examples (A) and (B) are the same --> <!-- (A) *ngIf paragraph --> <p *ngIf="condition"> Our heroes are true! </p> <!-- (B) [ngIf] with template --> <template [ngIf]="condition"> <p> Our heroes are true! </p> </template>