Components :

• For register component we use @Component meta-data annotation.
• Component is a directive which use shadow DOM to create encapsulate visual behavior called components.Components are typically used to create UI widgets.
• Component is used to break up the application into smaller components.
• Only one component can be present per DOM element.
• @View decorator or templateurl template are mandatory in the component.

Directives :

• For register directives we use @Directive meta-data annotation.
• Directives is used to add behavior to an existing DOM element.
• Directive is use to design re-usable components.
• Many directive can be used in a per DOM element.
• Directive don’t have View.