javascript - 如何使用 _.where 通过 ID 查找嵌套在对象数组中的对象？

Question

这是 JSON:

tree.json:

[
  {
    "objectId": "o3mH2lo8wO",
    "name": "Coeptis",
    "thumbnailUrl": "https://storage.googleapis.com/bundle_asia_dra/portal/buildingImg/Coeptis.png",
    "createdAt": "2015-06-29T08:16:51.897Z",
    "version": 0,
    "pano": []
  },
  {
    "objectId": "ueCCX8v4Qz",
    "name": "Sunflower",
    "thumbnailUrl": "https://storage.googleapis.com/bundle_asia_dra/portal/buildingButton/caisa.png",
    "createdAt": "2015-08-25T12:11:02.235Z",
    "version": 0,
    "space": "56-139",
    "pano": [
      {
        "objectId": "TIdm6sG1r0",
        "name": "D0",
        "panoData": [

我知道如何获取第一个对象(例如 "objectId": "ueCCX8v4Qz" ):

 _.where(tree, {"objectId": "ueCCX8v4Qz"})

但我不知道如何获取，例如"objectId": "TIdm6sG1r0" ( pano: 内数组内的对象)。

如何实现这一目标？

Answer 1

可以使用reduce和where的组合来遍历父元素并对指定的属性执行where。类似的东西

var tree = [{
  "objectId": "o3mH2lo8wO",
  "name": "Coeptis",
  "thumbnailUrl": "https://storage.googleapis.com/bundle_asia_dra/portal/buildingImg/Coeptis.png",
  "createdAt": "2015-06-29T08:16:51.897Z",
  "version": 0,
  "pano": []
}, {
  "objectId": "ueCCX8v4Qz",
  "name": "Sunflower",
  "thumbnailUrl": "https://storage.googleapis.com/bundle_asia_dra/portal/buildingButton/caisa.png",
  "createdAt": "2015-08-25T12:11:02.235Z",
  "version": 0,
  "space": "56-139",
  "pano": [{
    "objectId": "TIdm6sG1r0",
    "name": "D0",
    "panoData": []
  }]
}];


// register new function to be run on underscore
_.mixin({
  'nestedWhere': function(parent, childTarget, searchOptions) {
    
    // reduce the parent with an intial state set to an empty array that we push a parent
    // to if a child where clause is matched
    return _.reduce(parent, function(memo, parentElement) {
      if (_.where(parentElement[childTarget], searchOptions).length > 0) {
        memo.push(parentElement);
      }
      return memo;
    }, []);
  }
});


var data = _.nestedWhere(tree, "pano", {
  "objectId": "TIdm6sG1r0"
});

console.log(data)

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