React Hook for showing custom "Add to home screen" prompt

Demo:
Twitter

const [prompt, promptToInstall] = useAddToHomescreenPrompt();

Listens for beforeinstallprompt event, which notifies you when the browser would have shown the default dialog,
intercepts it and lets you take over and show the prompt whenever you please.

Browser support and requirements

Add to Home Screen

Browser support is still quite lacking. At the time of writing, only Chrome (Desktop + Android) is supported.

Implementation

import * as React from "react";

interface IBeforeInstallPromptEvent extends Event {
  readonly platforms: string[];
  readonly userChoice: Promise<{
    outcome: "accepted" | "dismissed";
    platform: string;
  }>;
  prompt(): Promise<void>;
}

export function useAddToHomescreenPrompt(): [
  IBeforeInstallPromptEvent | null,
  () => void
] {
  const [prompt, setState] = React.useState<IBeforeInstallPromptEvent | null>(
    null
  );

  const promptToInstall = () => {
    if (prompt) {
      return prompt.prompt();
    }
    return Promise.reject(
      new Error(
        'Tried installing before browser sent "beforeinstallprompt" event'
      )
    );
  };

  React.useEffect(() => {
    const ready = (e: IBeforeInstallPromptEvent) => {
      e.preventDefault();
      setState(e);
    };

    window.addEventListener("beforeinstallprompt", ready as any);

    return () => {
      window.removeEventListener("beforeinstallprompt", ready as any);
    };
  }, []);

  return [prompt, promptToInstall];
}

Example component

import * as React from "react";
import { useAddToHomescreenPrompt } from "./useAddToHomescreenPrompt";

export function ExampleComponent() {
  const [prompt, promptToInstall] = useAddToHomescreenPrompt();
  const [isVisible, setVisibleState] = React.useState(false);

  const hide = () => setVisibleState(false);

  React.useEffect(
    () => {
      if (prompt) {
        setVisibleState(true);
      }
    },
    [prompt]
  );

  if (!isVisible) {
    return <div />;
  }

  return (
    <div onClick={hide}>
      <button onClick={hide}>Close</button>
      Hello! Wanna add to homescreen?
      <button onClick={promptToInstall}>Add to homescreen</button>
    </div>
  );
}