Interface ReactiveController

packages/reactive-element/src/reactive-controller.ts:53–84

 * calling `requestUpdate()` on the host.
 */
export interface ReactiveController {
  /**
   * Called when the host is connected to the component tree. For custom
   * element hosts, this corresponds to the `connectedCallback()` lifecycle,
   * which is only called when the component is connected to the document.
   */
  hostConnected?(): void;

  /**
   * Called when the host is disconnected from the component tree. For custom
   * element hosts, this corresponds to the `disconnectedCallback()` lifecycle,
   * which is called the host or an ancestor component is disconnected from the
   * document.
   */
  hostDisconnected?(): void;

  /**
   * Called during the client-side host update, just before the host calls
   * its own update.
   *
   * Code in `update()` can depend on the DOM as it is not called in
   * server-side rendering.
   */
  hostUpdate?(): void;

  /**
   * Called after a host update, just before the host calls firstUpdated and
   * updated. It is not called in server-side rendering.
   *
   */
  hostUpdated?(): void;
}