docs: function ImmutableGlobal (moduleName, defaults) {
      // require valid module name
      this.assert(typeof moduleName === 'string' && moduleName.length > 0, 100)
      // store module name
      this.moduleName = moduleName
      // return existing instance if defined
      if (defined(globalData()[moduleName])) {
          return globalData()[moduleName]
      }
      // register instance
      globalData()[moduleName] = this
      // store defaults
      this.defaults = defaults
      // call reset to initialize data
      this.reset()
  }