message: platform: using enum instead of redundant OS type
diff: import { canUseDOM } from './dom';
  -enum OSList {
  +export enum OS {
  ANDROID = 'android',
  IOS = 'ios',
  }
  -export type OS = OSList.ANDROID | OSList.IOS;
  -
  -export const ANDROID: OS = OSList.ANDROID;
  -export const IOS: OS = OSList.IOS;
  +export const ANDROID = OS.ANDROID;
  +export const IOS = OS.IOS;
  export function platform(useragent?: string): OS {
  const ua = useragent || canUseDOM && navigator.userAgent || '';
  