selectOnPlatform.js

selectOnPlatform.js

/* @flow */

import { Platform } from 'react-native'

const PLATFORM_PREFERENCES = Object.freeze({
  ios: ['ios', 'mobile'],
  android: ['android', 'mobile'],
  web: ['web'],
})

type SelectOnPlatformValues<T> =
  | {|
      mobile: T,
      web: T,
    |}
  | {|
      ios: T,
      android: T,
      web: T,
    |}

export default <T>(values: SelectOnPlatformValues<T>): T => {
  const possibleKeys = PLATFORM_PREFERENCES[Platform.OS]
  const key = possibleKeys.find(key => values.hasOwnProperty(key))

  if (key === undefined) {
    throw new Error(`Cannot find value for current platform (${Platform.OS})`)
  }

  // $FlowFixMe
  const value: T = values[key]
  return value
}