param env returns export function is ( env ) { const ua = window . navigator . userAgent ; switch ( env . toLowerCase ( ) ) { case "ios" : return /iPhone|iPad/i . test ( ua ) ; case "android" : return /Android/i . test ( ua ) ; case "wechat" : return /MicroMessenger/i . test ( ua ) ; case "qq" : return /QQ/i . test ( ua ) ; case "alipay" : return /AlipayClient/i . test ( ua ) ; case "weibo" : return /Weibo/i . test ( ua ) ; case "douyin" : return /aweme/i . test ( ua ) ; case "touchable" : return window . ontouchstart !== undefined ; default : return false ; } }