function check(minVersions, strictMode, ua) {
    return !isUnsupportedBrowser(minVersions, strictMode, ua);
  }
Check if browser is supported

@param  {Object} minVersions map of minimal version to browser
@param  {Boolean} [strictMode = false] flag to return false if browser wasn't found in map
@param  {String}  [ua] user agent string
@return {Boolean}