ngInclude

ngInclude is a directive in the AngularJS framework used to include external HTML content into an existing HTML template. It allows developers to break down complex user interfaces into smaller, reusable components, thereby improving code organization and maintainability. When AngularJS encounters an ngInclude directive, it fetches the specified HTML file and inserts its content into the DOM at the location of the directive.

The primary attribute of ngInclude is its source URL, which can be a static path or a dynamically generated URL. This makes it flexible for loading different content based on application state or user interaction. The included content is compiled with the scope of the parent controller, allowing for data binding and interaction between the parent and the included template.

ngInclude is particularly useful for creating reusable components such as headers, footers, navigation bars, or any other distinct UI element that needs to be repeated across multiple views. By externalizing these components, the main HTML files become cleaner and easier to manage. The directive also supports options for controlling caching and error handling, further enhancing its utility in building robust single-page applications. It's a fundamental tool for achieving modularity in AngularJS development.