react-native 三角形

triangleLeft: {
  width: 0,
  height: 0,
  borderTopWidth: 10,
  borderTopColor: 'transparent',
  borderRightWidth: 10,
  borderRightColor: '#999',
  borderLeftWidth: 5,
  borderLeftColor: 'transparent',
  borderBottomWidth: 10,
  borderBottomColor: 'transparent',
}