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"})

但是我不知道如何获取例如"objectId": "TIdm6sG1r0" （位于pano:数组内部的对象）。

如何做到这一点？

Answer 1

可以结合使用reduce和where来遍历父元素，并在指定的属性上执行where。 就像是

 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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