ionic-framework/packages/react/src/components/createControllerComponent.tsx

import { OverlayEventDetail } from '@ionic/core';
import React from 'react';

import { attachProps } from './utils';

interface OverlayBase extends HTMLElement {
  present: () => Promise<void>;
  dismiss: (data?: any, role?: string | undefined) => Promise<boolean>;
}

export interface ReactControllerProps {
  isOpen: boolean;
  onDidDismiss?: (event: CustomEvent<OverlayEventDetail>) => void;
}

export const createControllerComponent = <OptionsType extends object, OverlayType extends OverlayBase>(
  displayName: string,
  controller: { create: (options: OptionsType) => Promise<OverlayType>; }
) => {
  const dismissEventName = `on${displayName}DidDismiss`;

  type Props = OptionsType & ReactControllerProps & {
    forwardedRef?: React.RefObject<OverlayType>;
  };

  class Overlay extends React.Component<Props> {
    overlay?: OverlayType;
    isUnmounted = false;

    constructor(props: Props) {
      super(props);
      this.handleDismiss = this.handleDismiss.bind(this);
    }

    static get displayName() {
      return displayName;
    }

    async componentDidMount() {
      const { isOpen } = this.props;
      if (isOpen as boolean) {
        this.present();
      }
    }

    componentWillUnmount() {
      this.isUnmounted = true;
      if (this.overlay) { this.overlay.dismiss(); }
    }

    async componentDidUpdate(prevProps: Props) {
      if (prevProps.isOpen !== this.props.isOpen && this.props.isOpen === true) {
        this.present(prevProps);
      }
      if (this.overlay && prevProps.isOpen !== this.props.isOpen && this.props.isOpen === false) {
        await this.overlay.dismiss();
      }
    }

    handleDismiss(event: CustomEvent<OverlayEventDetail<any>>) {
      if (this.props.onDidDismiss) {
        this.props.onDidDismiss(event);
      }
      if (this.props.forwardedRef) {
        (this.props.forwardedRef as any).current = undefined;
      }
    }

    async present(prevProps?: Props) {
      const { isOpen, onDidDismiss, ...cProps } = this.props;
      this.overlay = await controller.create({
        ...cProps as any
      });
      attachProps(this.overlay, {
        [dismissEventName]: this.handleDismiss
      }, prevProps);
      // Check isOpen again since the value could have changed during the async call to controller.create
      // It's also possible for the component to have become unmounted.
      if (this.props.isOpen === true && this.isUnmounted === false) {
        if (this.props.forwardedRef) {
          (this.props.forwardedRef as any).current = this.overlay;
        }
        await this.overlay.present();
      }
    }

    render(): null {
      return null;
    }
  }

  return React.forwardRef<OverlayType, Props>((props, ref) => {
    return <Overlay {...props} forwardedRef={ref} />;
  });
};