code: function featureNameFromProperty(instance, defaultName, candidateMap) {
    for (var key in candidateMap) {
      if (typeof instance[key] !== 'undefined') {
        return candidateMap[key];
      }
    }
  
    console.warn('no feature name detected for '+ defaultName +' using default');
    return defaultName;
  }
docs: Detects browser-specific names of browser features by checking availability
  of browser-specific properties in given object instance.
  
  @param {Object} instance object that will be checked for existence of properties
  @param {String} defaultName name used if nothing else detected (standard-compliant name)
  @param {Object} candidateMap browser-specific properties (keys) mapped to feature names (values)
  @return {String} value from candidateMap or defaultName