In Angular, a directive is a class that adds behavior to an existing HTML element, or extends the behavior of an HTML element by creating a new one. Directives can be used to manipulate the DOM, to add dynamic behavior to a web page, or to create custom HTML elements. There are two types of directives in Angular: structural and attribute.
A component, on the other hand, is a directive with a template. A component defines a reusable UI element, which can have its own behavior, input, and output properties. Components also manage their own state and rendering, and they are the building blocks of an Angular application.
The main difference between directives and components is that directives only add behavior to an existing HTML element, while components define a new UI element with its own behavior, input, and output properties. Components also have a lifecycle, which is managed by Angular, while directives do not.
In summary, a directive in Angular is a class that adds behavior to an existing HTML element, while a component is a directive with a template that defines a reusable UI element with its own behavior, input, and output properties. Components are the building blocks of an Angular application, while directives only add behavior to existing HTML elements.