A refactor of the old version as requested here in this tweet: https://twitter.com/sseraphini/status/1219701281331257345

useKeyboardSpace.js

import React from 'react'
import PropTypes from 'prop-types'
import { Keyboard, LayoutAnimation, Dimensions, Platform } from 'react-native'

const defaultAnimation = {
  duration: 500,
  create: {
    duration: 300,
    type: LayoutAnimation.Types.easeInEaseOut,
    property: LayoutAnimation.Properties.opacity,
  },
  update: {
    type: LayoutAnimation.Types.spring,
    springDamping: 200,
  },
}

export default function useKeyboardSpacer({
  topSpacing = 0,
  onChange = () => {},
}) {
  const [keyboardSpace, setKeyboardSpace] = React.useState(0)

  const onChangeRef = React.useRef()
  onChangeRef.current = onChange

  React.useEffect(() => {
    const updateListener =
      Platform.OS === 'android' ? 'keyboardDidShow' : 'keyboardWillShow'
    const resetListener =
      Platform.OS === 'android' ? 'keyboardDidHide' : 'keyboardWillHide'

    const updateKeyboardSpace = event => {
      if (!event.endCoordinates) {
        return
      }

      let animationConfig = defaultAnimation

      if (Platform.OS === 'ios') {
        animationConfig = LayoutAnimation.create(
          event.duration,
          LayoutAnimation.Types[event.easing],
          LayoutAnimation.Properties.opacity
        )
      }

      LayoutAnimation.configureNext(animationConfig)

      const newSpace =
        Dimensions.get('window').height -
        event.endCoordinates.screenY +
        topSpacing

      setKeyboardSpace(newSpace)

      onChangeRef.current(newSpace)
    }

    const resetKeyboardSpace = event => {
      let animationConfig = defaultAnimation

      if (Platform.OS === 'ios') {
        animationConfig = LayoutAnimation.create(
          event.duration,
          LayoutAnimation.Types[event.easing],
          LayoutAnimation.Properties.opacity
        )
      }

      LayoutAnimation.configureNext(animationConfig)

      setKeyboardSpace(0)
      onChangeRef.current(0)
    }

    Keyboard.addListener(updateListener, this.updateKeyboardSpace)
    Keyboard.addListener(resetListener, this.resetKeyboardSpace)

    return () => {
      Keyboard.removeListener(updateListener, updateKeyboardSpace)
      Keyboard.removeListener(resetListener, resetKeyboardSpace)
    }
  }, [topSpacing])

  return keyboardSpace
}

useKeyboardSpacer.propTypes = {
  topSpacing: PropTypes.number,
  onChange: PropTypes.func,
}