Angular - An Introduction to Structural Directives in Angular

In post Directive in Angular, we tried to understand what is directive? In this post, we'll explore Structural Directives and understand how they enhance the functionality and flexibility of Angular applications.

What are Structural Directives?

Structural Directives in Angular are a type of directive that modify the layout and structure of the DOM by adding or removing elements based on conditions. Unlike Attribute Directives, which change an element's behavior or appearance, Structural Directives directly impact the DOM's structure. The most commonly used Structural Directives in Angular are 'ngIf', 'ngFor', and 'ngSwitch'.

1. ngIf: The 'ngIf' directive conditionally adds or removes an element from the DOM based on the evaluation of an expression. It proves particularly useful when you need to show or hide specific parts of your template depending on your application's state. Example:

<ng-container *ngIf="isLoggedIn">
  <p>Welcome, {{ username }}!</p>
</ng-container>

In this example, the '<p>' element will only be rendered if the 'isLoggedIn' variable is true.

Angular - Understanding ng-template and ng-content in Angular

In Angular, the features 'ng-template' and 'ng-content' are valuable tools that facilitate the creation of dynamic and reusable components. They significantly contribute to improving code modularity, reusability, and maintainability. Let's explore each of these features to comprehend their importance in Angular development.

1. ng-template:

In Angular, 'ng-template' is a directive that allows the definition of a template block within a component without immediate rendering. It serves as a placeholder for content that can be instantiated later, based on different conditions. Think of it as a blueprint for creating content that will only be activated when explicitly used.

Usage:

<ng-template #myTemplate>
  
</ng-template>

How to use ng-template:

The true power of 'ng-template' comes into play when used in conjunction with other Angular directives such as 'ngIf', 'ngFor', and custom structural directives. For example, with 'ngIf', you can conditionally render content based on specific logic: