notesnook/apps/mobile/app/hooks/use-keyboard.ts

import { useEffect, useState } from "react";
import { Keyboard, KeyboardEventListener, ScreenRect } from "react-native";

const emptyCoordinates = Object.freeze({
  screenX: 0,
  screenY: 0,
  width: 0,
  height: 0
});
const initialValue = {
  start: emptyCoordinates,
  end: emptyCoordinates
};

export default function useKeyboard() {
  const [shown, setShown] = useState(false);
  const [coordinates, setCoordinates] = useState<{
    start: undefined | ScreenRect;
    end: ScreenRect;
  }>(initialValue);
  const [keyboardHeight, setKeyboardHeight] = useState<number>(0);

  const handleKeyboardWillShow: KeyboardEventListener = (e) => {
    setCoordinates({ start: e.startCoordinates, end: e.endCoordinates });
  };
  const handleKeyboardDidShow: KeyboardEventListener = (e) => {
    setShown(true);
    setCoordinates({ start: e.startCoordinates, end: e.endCoordinates });
    setKeyboardHeight(e.endCoordinates.height);
  };
  const handleKeyboardWillHide: KeyboardEventListener = (e) => {
    setCoordinates({ start: e.startCoordinates, end: e.endCoordinates });
  };
  const handleKeyboardDidHide: KeyboardEventListener = (e) => {
    setShown(false);
    if (e) {
      setCoordinates({ start: e.startCoordinates, end: e.endCoordinates });
    } else {
      setCoordinates(initialValue);
      setKeyboardHeight(0);
    }
  };

  useEffect(() => {
    const subscriptions = [
      Keyboard.addListener("keyboardWillShow", handleKeyboardWillShow),
      Keyboard.addListener("keyboardDidShow", handleKeyboardDidShow),
      Keyboard.addListener("keyboardWillHide", handleKeyboardWillHide),
      Keyboard.addListener("keyboardDidHide", handleKeyboardDidHide)
    ];

    return () => {
      subscriptions.forEach((subscription) => subscription.remove());
    };
  }, []);
  return {
    keyboardShown: shown,
    coordinates,
    keyboardHeight
  };
}