userAgent检测各种设备

const ua = window.navigator.userAgent.toLowerCase()

使用test(返回boolean)或match(返回匹配字符)或indexOf(判断-1返回boolean)都行

isWindowsPhone(){ return /(?:windows phone)/.test(ua)}
isSymbian (){ return /(?:symbianos)/.test(ua) || isWindowsPhone}
isAndroid (){ return /(?:android)/.test(ua)}
isFireFox (){ return /(?:firefox)/.test(ua)}
isChrome (){ return /(?:chrome|crios)/.test(ua)}
isTablet (){ return /(?:ipad|playbook)/.test(ua) || (isandroid && !/(?:mobile)/.test(ua)) || (isfirefox && /(?:tablet)/.test(ua))}
isPhone (){ return /(?:iphone)/.test(ua) && !isTablet}
isPc (){ return  !isPhone && !isAndroid && !isSymbian}
isWechatdevtools (){ return /wechatdevtools/.test(ua)}
isMac(){return window.navigator.platform.toLocaleLowerCase().indexOf('mac') > -1 }
isMicromessenger(){return /micromessenger/.test(ua)}

判断小程序运行于哪个环境

function isWhat(){
    wx.getSystemInfo({
        success:function(res){
            if(res.platform == "devtools"){
                return 'devtools'
            }else if(res.platform == "ios"){
                return 'IOS'
            }else if(res.platform == "android"){
                return 'android'
            }
        }
    })
  }
}