code: function makeFinder(exts) {
    return function (base, req) {
      for (var i = 0; i < exts.length; i += 1) {
        var ext = exts[i]
          , attempt = join(base, req + ext);
  
        if (exists(attempt)) {
          return (req + ext);
        }
      }
      return false;
    };
  }
docs: makeFinder
  
  finder factory for Resolver
  @return finder function
  
  finder function scans join(base, req + ext) for closure held extensions