ng-template is an Angular element that is used for rendering HTML in a template. However, it is not rendered directly on DOM. If you include an ng-template tag to a template, the tag and the content inside it will be replaced by comment upon render.
ng-container allows us to create a division or section in a template without introducing a new HTML element. The ng-container does not render in the DOM, but content inside it is rendered. ng-container is not a directive, component, class, or interface, but just a syntax element.
So ng-container is useful when you want to conditionaly append a group of elements (ie using *ngIf="foo" ) in your application but don't want to wrap them with another element. That's a good point. I guess that it differs from <template> when it's used without directives. <template> would just produce <!
Passing data to ngTemplateOutletWe can also pass data to the using its second property ngTemplateOutletContext . Alternatively you can also use the following syntax. Pass more than one value.
<ng-container>
to the rescueThe Angular
<ng-container>
is a grouping element that doesn't interfere with styles or layout because Angular doesn't put it in the DOM.
(...)
The
<ng-container>
is a syntax element recognized by the Angular parser. It's not a directive, component, class, or interface. It's more like the curly braces in a JavaScript if-block:if (someCondition) {
statement1;
statement2;
statement3;
}
Without those braces, JavaScript would only execute the first statement when you intend to conditionally execute all of them as a single block. The
<ng-container>
satisfies a similar need in Angular templates.
According to this pull request :
<ng-container>
is a logical container that can be used to group nodes but is not rendered in the DOM tree as a node.
<ng-container>
is rendered as an HTML comment.
so this angular template :
<div>
<ng-container>foo</ng-container>
<div>
will produce this kind of output :
<div>
<!--template bindings={}-->foo
<div>
So ng-container
is useful when you want to conditionaly append a group of elements (ie using *ngIf="foo"
) in your application but don't want to wrap them with another element.
<div>
<ng-container *ngIf="true">
<h2>Title</h2>
<div>Content</div>
</ng-container>
</div>
will then produce :
<div>
<h2>Title</h2>
<div>Content</div>
</div>
The documentation (https://angular.io/guide/template-syntax#!#star-template) gives the following example. Say we have template code like this:
<hero-detail *ngIf="currentHero" [hero]="currentHero"></hero-detail>
Before it will be rendered, it will be "de-sugared". That is, the asterix notation will be transcribed to the notation:
<template [ngIf]="currentHero">
<hero-detail [hero]="currentHero"></hero-detail>
</template>
If 'currentHero' is truthy this will be rendered as
<hero-detail> [...] </hero-detail>
But what if you want an conditional output like this:
<h1>Title</h1><br>
<p>text</p>
.. and you don't want the output be wrapped in a container.
You could write the de-sugared version directly like so:
<template [ngIf]="showContent">
<h1>Title</h1>
<p>text</p><br>
</template>
And this will work fine. However, now we need ngIf to have brackets [] instead of an asterix *, and this is confusing (https://github.com/angular/angular.io/issues/2303)
For that reason a different notation was created, like so:
<ng-container *ngIf="showContent"><br>
<h1>Title</h1><br>
<p>text</p><br>
</ng-container>
Both versions will produce the same results (only the h1 and p tag will be rendered). The second one is preferred because you can use *ngIf like always.
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