CODEWITHSUNDEEP
angulartypescript
Brian Leach
Brian Leach

Reputation: 4154

What is the difference between ngFor and *ngFor

I cannot find a good description of the differences anywhere. Same with *ngIf and ngIf

An example of *ngFor

<li *ngFor="let video of page" ...>
  <img src="api/Videos/{{video.id}}/thumbnail">
</li>

and an example of ngFor

<template ngFor let-labelid [ngForOf]="labelLookup | keyValueFilter" >
  <label  [ngStyle]="{'background-color': labelLookup[labelid].color}">
    <input (click)="changeLabel(labelid)" type="radio" name="labelSelector" value="{{ labelid }}" [checked]="labelid == 1">
  </label>
</template>

Upvotes: 9

Views: 7508

Answers (1)

G&#252;nter Z&#246;chbauer
G&#252;nter Z&#246;chbauer

Reputation: 657058

The difference is that *ngFor is converted to <template ngFor [ngForOf]="..." internally.

They are equivalent but the former is more convenient to write.

The explicit version (<template ngFor ...>) allows to apply the directive to multiple elements at once while the implicit version (shorthand) only wraps the element where it is applied to with the <template> tag.

With Angular 2.0.0 final the <ng-container> element was added that allows to use the shorthand syntax on an element that behaves like the <template> element (is not added to the DOM).

See also

Upvotes: 8

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