lodash group按键嵌套对象的数组

Question

我有以下数据：

  var data = {
  "features": [
    {
      "properties": {
        "route_id": 522,
        "name": "the Mekong",
        "tour_id": 538
      }
    },{
      "properties": {
        "route_id": 522,
        "name": "Cambodia & the Mekong",
        "tour_id": 545
      }
    },{
      "properties": {
        "route_id": 521,
        "name": "Cambodia",
        "tour_id": 537
      }
    }
  ]
}

现在，我想将具有类似"route_id"的值分组为嵌套的对象数组;最终使用lodash;以便预期结果如下：

var result = {
  "features": [
    {
      "properties": [{
        "route_id": 522,
        "name": "the Mekong",
        "tour_id": 538
        },{
        "route_id": 522,
        "name": "Cambodia & the Mekong",
        "tour_id": 545
      }]
    },{
      "properties": {
        "route_id": 521,
        "name": "Cambodia",
        "tour_id": 537
      }
    }
  ]
}

我尝试使用_.group，但我不知道如何在一个对象下获得嵌套数组。另请注意，"properties"键会有其他键，但它们与结构无关。

Answer 1

如果features集合中的对象包含一个密钥properties，那么我强烈建议规范化结构，删除properties密钥。不过，这是您可能正在寻找的实现。

var result = {
  features: _(data.features)
    // get all routes (get rid of properties key)
    .map('properties') 
    // group by route_id
    .groupBy('route_id') 
    // place properties key again
    .map(function(group) { return { properties: group };})
    // get grouped features
    .value()
};

功能参考：lodash#map，lodash#groupBy

var data = {
  "features": [{
    "properties": {
      "route_id": 522,
      "name": "the Mekong",
      "tour_id": 538
    }
  }, {
    "properties": {
      "route_id": 522,
      "name": "Cambodia & the Mekong",
      "tour_id": 545
    }
  }, {
    "properties": {
      "route_id": 521,
      "name": "Cambodia",
      "tour_id": 537
    }
  }]
};

var result = {
  features: _(data.features)
    // get all routes (get rid of properties key)
    .map('properties') 
    // group by route_id
    .groupBy('route_id') 
    // place properties key again
    .map(function(group) { return { properties: group };})
    // get grouped features
    .value()
};
  
console.log(result);

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Answer 2

在jquery中你可以使用$ .extend（obj1，obj2）;