watson-speech/speech-to-text/result-stream.js

IBM Watson Speech to Text and Text to Speech SDK for web browsers.

/**
 * Copyright 2014 IBM Corp. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

'use strict';

var { Transform } = require('readable-stream');
var util = require('util');
var clone = require('clone');

/**
 * Object-Mode stream that pulls result objects from the results array
 *
 * Also copies the top-level result_index to the individual results as .index
 *
 * @constructor
 * @param {Object} options
 */
function ResultStream(options) {
  options = options || {};
  options.objectMode = true;
  Transform.call(this, options);
}
util.inherits(ResultStream, Transform);

ResultStream.prototype._transform = function(data, encoding, next) {
  // when speaker_labels is enabled, some messages won't have a results array
  if (Array.isArray(data.results)) {
    // usually there is exactly 1 result, but there can be 0 in some circumstances, and potentially more in future iterations
    data.results.forEach(function(result) {
      var cloned = clone(result);
      cloned.index = data.result_index;
      this.push(cloned);
    }, this);
  } else {
    this.push(data);
  }
  next();
};

ResultStream.prototype.promise = require('./to-promise');

module.exports = ResultStream;