What it does
Marks a class as an Angular directive and collects directive configuration metadata.
How to use
import {Directive} from '@angular/core'; @Directive({ selector: 'my-directive', }) export class MyDirective { }
Description
Directive decorator allows you to mark a class as an Angular directive and provide additional metadata that determines how the directive should be processed, instantiated and used at runtime.
Directives allow you to attach behavior to elements in the DOM..
A directive must belong to an NgModule in order for it to be usable
by another directive, component, or application. To specify that a directive is a member of an
NgModule,
you should list it in the declarations field of that NgModule.
In addition to the metadata configuration specified via the Directive decorator, directives can control their runtime behavior by implementing various Life-Cycle hooks.
Metadata Properties:
- exportAs - name under which the component instance is exported in a template
- host - map of class property to host element bindings for events, properties and attributes
- inputs - list of class property names to data-bind as component inputs
- outputs - list of class property names that expose output events that others can subscribe to
- providers - list of providers available to this component and its children
- queries - configure queries that can be injected into the component
- selector - css selector that identifies this component in a template
exported from @angular/core/index defined in @angular/core/src/metadata/directives.ts