Method buildCallback

src/preact/base-element.js:376–457

@override

()

  /** @override */
  buildCallback() {
    const Ctor = /** @type {typeof PreactBaseElement} */ (
      /** @type {?} */ (this.constructor)
    );

    this.observer = new MutationObserver((rs) => this.checkMutations_(rs));
    const {props} = Ctor;
    const childrenInit = checkPropsFor(props, HAS_SELECTOR)
      ? CHILDREN_MUTATION_INIT
      : null;
    const passthroughInit = checkPropsFor(props, HAS_PASSTHROUGH)
      ? PASSTHROUGH_MUTATION_INIT
      : null;
    const templatesInit = Ctor.usesTemplate ? TEMPLATES_MUTATION_INIT : null;
    this.observer.observe(this.element, {
      attributes: true,
      ...childrenInit,
      ...passthroughInit,
      ...templatesInit,
    });

    this.mediaQueryProps_ = checkPropsFor(props, HAS_MEDIA)
      ? new MediaQueryProps(this.win, () => this.scheduleRender_())
      : null;

    const {staticProps} = Ctor;
    const initProps = this.init();
    Object.assign(this.defaultProps_, staticProps, initProps);

    this.checkPropsPostMutations();

    // Unmount callback.
    subscribe(this.element, [], () => {
      return () => {
        this.mounted_ = false;
        if (this.container_) {
          // We have to unmount the component to run all cleanup functions and
          // release handlers. The only way to unmount right now is by
          // unrendering the DOM. If the new `unmount` API becomes available, this
          // code can be changed to `unmount` and the follow up render would
          // have to execute the fast `hydrate` API.
          render(null, this.container_);
        }
      };
    });

    // Unblock rendering on first `CanRender` response. And keep the context
    // in-sync.
    subscribe(
      this.element,
      /** @type {import('#core/context').IContextProp<*, boolean>[]} */ ([
        CanRender,
        CanPlay,
        LoadingProp,
      ]),
      (canRender, canPlay, loading) => {
        this.context_.renderable = canRender;
        this.context_.playable = canPlay;