code: function parse(opts, callback) {
      assert.object(opts, 'opts');
      assert.string(opts.body, 'opts.body');
      assert.func(callback, 'callback');
  
      const sourceStream = intoStream(opts.body);
      const parseStream = createParseStream();
      const cb = once(callback);
  
      parseStream.on('data', function(data) {
          return cb(null, data);
      });
  
      parseStream.on('error', function(err) {
          return cb(err);
      });
  
      sourceStream.pipe(parseStream);
  }
docs: stream based JSON.parse. async function signature to abstract over streams.
  @public
  @param {Object} opts options to pass to parse stream
  @param {String} opts.body string to parse
  @param {Function} callback a callback function
  @return {Object} the parsed JSON object