Javascript 组合GeoJSON

我有一些单独的GeoJSON对象，例如

 var fc = {
    "type": "FeatureCollection",
     "features": [
      {
        "type": "Feature",
        "properties": {
           "time": 1369786338000
         },
        "geometry": {
           "type": "Point",
           "coordinates": [19.026432, 47.49134]
         }
       }, {
        "type": "Feature",
        "properties": {
           "time": 1369786340000
         },
        "geometry": {
           "type": "Point",
           "coordinates": [19.074497, 47.509548]
        }
      }
    ]
  };

我怎样才能把它组合成这样的东西

var combine = {
"type": "FeatureCollection",
 "features": [
  {
    "type": "Feature",
    "properties": {
       "time": [
          1369786338000,
          1369786340000
        ]
     },
    "geometry": {
      "type": "MultiPoint",
       "coordinates": [
          [19.026432, 47.49134],
          [19.074497, 47.509548]
        ]

我正在尝试使用，但出现如下错误

 turf.combine is not a function

当我尝试将GeoJSON组合在一起时。 我已经定义了我的地盘，例如

var turf = require('turf-combine')

多谢各位