code: function loadPrettyGraphSON(graph, filename, callback) {
          // We need to create an input stream and a reader, both of which are created asyncrously in parallel.
          // It would be nice to use Bluebird.join() perform those two operations, but the declaration for join()
          // in bluebird.d.ts isn't correct. We instead use .all(), and furthermore we use these two local variables
          // to commuicate the results of the two async operations to the final join operation.
          var theStream;
          var theReader;
          function getStream() {
              var readFileP = BluePromise.promisify(fs.readFile);
              return readFileP(filename, 'utf8')
                  .then(function (jsonText) {
                  var jsonObjArray = JSON.parse(jsonText);
                  var jsonTextArray = _.map(jsonObjArray, JSON.stringify);
                  return jsonTextArray.join('\n');
              })
                  .then(function (uglyText) {
                  var StringInputStream = Tinkerpop.autoImport('StringInputStream');
                  theStream = StringInputStream.from(uglyText);
                  return theStream;
              });
          }
          function getGraphReader() {
              return Tinkerpop.GraphSONReader.buildP()
                  .then(function (builder) {
                  return _newGraphSONMapper()
                      .then(function (mapper) { return builder.mapperP(mapper); });
              })
                  .then(function (builder) { return builder.createP(); })
                  .then(function (reader) { theReader = reader; return theReader; });
          }
          return BluePromise.all([getStream(), getGraphReader()])
              .then(function () { return theReader.readGraphP(theStream, graph); })
              .then(function () { return graph; })
              .nodeify(callback);
      }
docs: ### `loadPrettyGraphSON(graph: Java.Graph, filename: string)` Loads the graph as GraphSON, and returns promise to the graph (for fluent API).