区分iphoneX和iphone12

移动端开发时，iphoneX和iphone12都采用了刘海屏，为了适配顶部状态栏，需要区分当前设备是否为iphoneX和iphone12。

import {Dimensions, Platform} from '@mrn/react-native'
// 获取设备屏幕宽高
export const screenW = Dimensions.get('window').width
export const screenH = Dimensions.get('window').height
// 比较当前设备和对照设备的屏幕宽高
function matchIOSScreenSize(screenWidth: number, screenHeight: number) {
  return (
    Platform.OS === 'ios' &&
    ((screenH === screenHeight && screenW === screenWidth) || (screenH === screenWidth && screenW === screenHeight))
  )
}
// 根据iphoneX和iphone12的宽高，和当前设备宽高进行比较
function isIphoneX() {
  // iPhone X和iPhone XS
  const widthX = 375
  const heightX = 812
  // iPhone XR和iPhone XS Max
  const widthXSM = 414
  const heightXSM = 896
  // iPhone 12
  const width12 = 390
  const height12 = 844
  return (
    matchIOSScreenSize(widthX, heightX) ||
    matchIOSScreenSize(widthXSM, heightXSM) ||
    matchIOSScreenSize(width12, height12)
  )
}