code: function _cacher(content, filename, basedir, userResolver) {
    try {
      detective(content).map(moduleId=>{
        if (!userResolver.isCoreModule(moduleId)) {
          userResolver.resolve(moduleId, basedir).then(modulePath=>{
            if (!cache.has(modulePath) && !fileCache.has(modulePath)) {
              _loadModuleText(modulePath, filename).then(content=> {
                const _userResolver = new Resolver(Object.assign({}, userResolver, {basedir: path.dirname(modulePath)}));
                return _cacher(content, modulePath, path.dirname(modulePath), _userResolver)
              });
            }
          }, err=>true);
        }
      });
    } catch(err) {
  
    }
  }
docs: Try to pre-load requires by parsing the loaded text for requires (and descendants).
  
  @private
  @param {string|Buffer} content     The module content.
  @param {string} filename           The module filename.
  @param {string} basedir            The module basedir.
  @param {Resolver} userResolver     The Resolver used.