src/lib/hooks/useInitialNumToRender.ts


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

import {useWindowDimensions} from 'react-native'
import {useSafeAreaInsets} from 'react-native-safe-area-context'

import {useBottomBarOffset} from 'lib/hooks/useBottomBarOffset'

const MIN_POST_HEIGHT = 100

export function useInitialNumToRender({
  minItemHeight = MIN_POST_HEIGHT,
  screenHeightOffset = 0,
}: {minItemHeight?: number; screenHeightOffset?: number} = {}) {
  const {height: screenHeight} = useWindowDimensions()
  const {top: topInset} = useSafeAreaInsets()
  const bottomBarHeight = useBottomBarOffset()

  const finalHeight =
    screenHeight - screenHeightOffset - topInset - bottomBarHeight

  const minItems = Math.floor(finalHeight / minItemHeight)
  if (minItems < 1) {
    return 1
  }
  return minItems
}