What is the purpose of Ng-container in Angular? 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.
What is “ng-container” in angular?
It can act as a container for other elements which is not actually rendered on the screen. So it can be rendered as a parent element for others We can use “ng-container”, where multiple Structural Directives are required. By design, Angular cannot have multiple structural directives on the same components. We can do the same with “ng-container”
Why replace a div with an NG-container?
Replacing the div with an ng-container resolves this issue: Having valid HTML will satisfy stricter tests and requirements and ensure support across browsers and devices. In this article, you explored the problems that ng-container addresses in your Angular applications, like redundant elements and invalid HTML standards.
What are the downsides of using ng-container?
One downside is that this approach is it introduces a redundant div element to the DOM: This is where the ng-container element becomes useful. The following behaves exactly the same, but without adding any extra element to the DOM at runtime: This would result in the following markup:
How to display conditional templates using ng-container in HTML?
“ng-container” can be used to display conditional templates. We can select template to be displayed on the basis of certain conditions. As the name suggests, “ng-container” can be used as a container element to enclose other elements. It acts as the parent which is itself not displayed on the screen then the application is rendered.
What is the purpose of Ng-container in Angular?
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Why We Should Use ng-container?
To sum up, ng-content is used to display children in a template, ng-container is used as a non-rendered container to avoid having to add a span or a div, and ng-template allows you to group some content that is not rendered directly but can be used in other places of your template or you code.
Can we give class to Ng-container?
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.
What is Ng-container vs ng template?
ng-container serves as a container for elements which can also accept structural directives but is not rendered to the DOM, while ng-template allows you to create template content that is not rendered until you specifically (conditionally or directly) add it to the DOM.
What is ng container?
ng-container is an element available in Angular 2+ that can act as the host to structural directives.
Why reduce markup in a DOM tree?
Reducing the amount of markup in your application ultimately results in a smaller DOM tree and can help avoid side effects with Cascading Style Sheet selectors.
Can you have more than one template binding in Angular?
In Angular, you cannot use more than one template binding on an element. This example combining *ngIf and *ngFor structural directives will not compile: Attempting to compile this code will result in the following error: Can't have multiple template bindings on one element.
Can ng container fix invalid HTML?
ng-container can also resolve the problem of invalid HTML markup in situations where using a div or span would not be valid HTML.
What is ng container in Angular?
What is Ng-container in Angular? “ng-container” is a logical container that can contain multiple elements within it . ng-container is not rendered on the screen as an element, instead, it is displaced as a comment in HTML. We can group components within ng-container, since it is not rendered as an HTML tag, it does not interface with styles ...
What is ng container?
As the name suggests, “ng-container” can be used as a container element to enclose other elements. It acts as the parent which is itself not displayed on the screen then the application is rendered.
Can ng container be used as parent element?
The example given above shows that the “ng-container” can be used as a parent element for other element without being rendered.
Is there a container for H1 and H2 tags?
In the output above, we can see that there is no container that is rendered for H1 and H2 Tag. Instead, we can see a comment “ng-container”.
Can ng container be used at multiple places?
TechnoFunnel presents another article to learn and understand use cases for “ng-container”. “ng-container” can be used at multiple places and can resolve multiple issues. Let's look for the use case scenarios when “ ng-container ” would be very useful during development.
Can Angular have multiple structural directives?
By design, Angular cannot have multiple structural directives on the same components. We can do the same with “ng-container”. “ng-container” can be used to display conditional templates. We can select template to be displayed on the basis of certain conditions.
What is the ng container directive?
As we can see, the ng-container directive provides us with an element that we can attach a structural directive to a section of the page, without having to create an extra element just for that.
What is ng template?
Like the name indicates, the ng-template directive represents an Angular template: this means that the content of this tag will contain part of a template, that can be then be composed together with other templates in order to form the final component template.
What is an uncaught error in template parse?
Uncaught Error: Template parse errors: Can't have multiple template bindings on one element. Use only one attribute named 'template' or prefixed with *
Can you add ngTemplateOutlet to a template?
We could add as many ngTemplateOutlet tags to the page as we would like, and instantiate a number of different templates. The value passed to this directive can be any expression that evaluates into a template reference, more on this later.
Is ng template tag normal?
This is normal and it's the expected behavior. This is because with the ng-template tag we are simply defining a template, but we are not using it yet.
Does ngif create a second implicit template?
But besides that else template, the use of ngIf also creates a second implicit ng-template! Let's have a look at what is happening under the hood:
Can you use ng container directives together?
These directives are frequently used with ng-container, and because these directives are designed to be used together, it will help if we learn them all in one go, as we will have more context around each directive.
What is ngif Angular?
Shown above is the Angular interpretation of *ngIf. Angular puts the host element to which the directive is applied within <ng-template> and keeps the host as it is. The final DOM is similar to what we have seen at the beginning of this article:
What is ng templatelet?
*ngTemplateOutlet is used for two scenarios — to insert a common template in various sections of a view irrespective of loops or condition and to make a highly configured component.
What is Angular grouping?
The Angular <ng-container> is a grouping element that doesn't interfere with styles or layout because Angular doesn't put it in the DOM. So if we write our Example 1 with <ng-container>: Example 1 with <ng-container>. We get the final DOM as: Final rendered DOM with <ng-container>.
What if you could decide which content should be placed where?
What if you could decide which content should be placed where? Instead of every content projected inside a single <ng-content>, you can also control how the contents will get projected with the select attribute of <ng-content>. It takes an element selector to decide which content to project inside a particular <ng-content>.
What is the second use case for *ngTemplateOutlet?
The second use case for *ngTemplateOutlet is highly customized components. Consider our previous example of <project-content> component with some modifications:
Does Angular wrap the host element?
These template elements only work in the presence of structural directives. Angular wraps the host element (to which the directive is applied) inside <ng-template> and consumes the <ng-template> in the finished DOM by replacing it with diagnostic comments.
Does Angular replace diagnostic comments?
This was the expected result. As we have already discussed, Angular replaces the <ng-template> with diagnostic comments. No doubt the above code would not generate any error, as Angular is perfectly fine with your use case. You would never get to know what exactly happened behind the scenes.
What is ng template?
ng-template is a virtual element and its contents are displayed only when needed (based on conditions).
What does the asterisk mean in Angular?
When you use a structural directive in Angular we will add a prefix asterisk (*) before the directive name. This asterisk is short hand notation for ng-template.
What is ngswitch in a switch?
NgSwitch controls the behavior of the other two switch directives ngSwitchCase and ngSwitchDefault.
Is ng-template a true element?
ng-template is not exactly a true web element. When we compile our code, we will not see a ng-template tag in HTML DOM.
Does ng-template work in div?
If you see the output it will display only ng-template works which is in div element.And have a look at the generated HTML source code.
Can you use asterisks in ng-template?
You might be thinking that why we need to use asterisk (*) notation when we can use ng-template element directly. Yes we can use ng-template instead of short hand notation.
When to use ng container?
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.
What is Angular grouping?
The 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.
Is ng container mentioned in the official documentation?
ng-container is mentioned in the official documentation but I'm still trying to understand how it works and what are use cases.
Does the ng container directive fall away?
Be aware that the ng-container directive falls away instead of a template where its directive wraps the actual content.
Prerequisites
Using ng-container to Avoid Redundant Elements
- In Angular, you cannot use more than one template binding on an element. This example combining *ngIf and *ngForstructural directives will not compile: Attempting to compile this code will result in the following error: One workaround would be to separate the template bindings and create a wrapper: One downside is that this approach is it introduce...
Using ng-container to Ensure Valid Html Standards
- ng-container can also resolve the problem of invalid HTML markup in situations where using a div or spanwould not be valid HTML. The following example would produce invalid HTML because li elements are expected to the be the direct children of the ulelement: Replacing the div with an ng-containerresolves this issue: Having valid HTML will satisfy stricter tests and requirements and …
Conclusion
- In this article, you explored the problems that ng-containeraddresses in your Angular applications, like redundant elements and invalid HTML standards. If you’d like to learn more about Angular, check out our Angular topic pagefor exercises and programming projects.