code: function initVar (key, envKey, def) {
          var negate = !def;
          switch (true) {
              case cacheObj.hasOwnProperty(key):
                  return cacheObj[key];
              case process.env.hasOwnProperty(envGlobalCacheKey):
                  return process.env[envGlobalCacheKey] !== '';
              case process.env.hasOwnProperty(envKey):
                  return negate ? process.env[envKey] === 'YES' : process.env[envKey] !== 'NO';
              default:
                  return def;
          }
      }
docs: cache variable initializer
  @param {String} key
  @param {String} envKey
  @param {Boolean} def
  @returns {Boolean}