ng-template
Angular's <ng-template> element defines a template that is not rendered by default.
Angular's <ng-template> element defines a template that is not rendered by default.
With <ng-template>, you can define template content that is only being rendered by Angular when
you, whether directly or indirectly, specifically instruct it to do so, allowing you to have full
control over how and when the content is displayed.
Note that if you wrap content inside an <ng-template> without instructing Angular to render it,
such content will not appear on a page. For example, see the following HTML code, when handling it
Angular won't render the middle "Hip!" in the phrase "Hip! Hip! Hooray!" because of the
surrounding <ng-template>.
<p>Hip!</p> <ng-template> <p>Hip!</p> </ng-template> <p>Hooray!</p>
Usage notes
Structural Directives
One of the main uses for <ng-template> is to hold template content that will be used
by Structural directives. Those directives can add and remove copies
of the template content based on their own logic.
When using
the structural directive shorthand,
Angular creates an <ng-template> element behind the scenes.
TemplateRef
<ng-template> elements are represented as instances of the TemplateRef class.
To add copies of the template to the DOM, pass this object to the ViewContainerRef
method createEmbeddedView().
Template Variables
<ng-template> elements can be referenced in templates
using standard template variables.
This is how <ng-template> elements are used as ngIf else clauses.
Such template variables can be used in conjunction with ngTemplateOutlet directives to render the
content defined inside <ng-template> tags.
Querying
A Query (such as ViewChild) can find the TemplateRef associated to
an <ng-template> element so that it can be used programmatically; for instance, to pass it to
the ViewContainerRef method createEmbeddedView().
Context
Inside the <ng-template> tags you can reference variables present in the surrounding outer
template.
Additionally, a context object can be associated with <ng-template> elements.
Such an object contains variables that can be accessed from within the template contents via
template (let and as) declarations.