Buffered result loses a polygon from a MultiPolygon about turf-buffer HOT 2 OPEN

var bufferOp = function(feature, radius) {
  var reader = new jsts.io.GeoJSONReader();
  var parser = new jsts.io.GeoJSONParser();
  var geom, buffered, polyCoord, polyGeom;

  var mulitCoords = [];
  if (feature.geometry.type === 'MultiPolygon') {
    // Work around a bug where jsts drops entire polygons from multipolygons
    for (var i = 0; i < feature.geometry.coordinates.length; i++) {
      polyCoord = feature.geometry.coordinates[i];
      polyGeom = {
        type: 'Polygon',
        coordinates: polyCoord
      };
      geom = reader.read(JSON.stringify(polyGeom));
      buffered = geom.buffer(radius);
      buffered = parser.write(buffered);
      mulitCoords.push(buffered.coordinates);
    }
    buffered.type = 'MultiPolygon';
    buffered.coordinates = mulitCoords;
  } else {
    geom = reader.read(JSON.stringify(feature.geometry));
    buffered = geom.buffer(radius);
    buffered = parser.write(buffered);
  }

  return {
    type: 'Feature',
    geometry: buffered,
    properties: feature.properties
  };
};