Not able to push an object into parent array by identifying the parent id of the object in javascript

问题

I'm having a JSON array with properties as id and parentActivityId.

$scope.data = [
    {
        id: 1,
        activityName: "Drilling",
        parentActivityId: 0,
        items: [
            {
                id: 2,
                activityName: "Blasting",
                parentActivityId: 1,
                items: [
                    {
                        id: 3,
                        activityName: "Ann",
                        parentActivityId: 2,
                        items: [],

                    },
                    {
                        id: 4,
                        activityName: "Ann",
                        parentActivityId: 2,
                        items: [],

                    }
                ]
            },
            {
                id: 5,
                activityName: "Transport",
                parentActivityId: 1,
                items: [
                    {
                        id: 6,
                        activityName: "Daniel",
                        parentActivityId: 5,
                        items: [],
                    }
                ]
            }
        ]
    }
];

I would like to push a new item based on the parentActiityId.The new item will be having a new id. Example:If my object is like this:

{
    id: 7,
    activityName: "Drilling",
    parentActivityId: 1,
    items: []
}

then my object will look like this..

 $scope.data = [
        {
            id: 1,
            activityName: "Drilling",
            parentActivityId: 0,
            items: [
                {
                    id: 2,
                    activityName: "Blasting",
                    parentActivityId: 1,
                    items: [
                        {
                            id: 3,
                            activityName: "Ann",
                            parentActivityId: 2,
                            items: [],

                        },
                        {
                            id: 4,
                            activityName: "Ann",
                            parentActivityId: 2,
                            items: [],

                        },
                    {
                         id: 7,
                         activityName: "Drilling",
                         parentActivityId: 2,
                         items: [],
                     }
                    ]
                },
                {
                    id: 5,
                    activityName: "Transport",
                    parentActivityId: 1,
                    items: [
                        {
                            id: 6,
                            activityName: "Daniel",
                            parentActivityId: 5,
                            items: [],
                        }
                    ]
                }
            ]
        }
    ];

I tried by giving this for loop..

var arrObj = {
    id: 7,
    activityName: "Drilling",
    parentActivityId: 1,
    items: []
};

function populateObj(arrObj) {
   for (var i = 0; i < $scope.data.length; i++) {
        if ($scope.data[i].id == arrObj.parentActivityId) {
            $scope.data.push(arrObj);
        }
    }
};

populateObj(arrObj);

which will push only to the parent.I want to identify the child as well in the for loop and the push to the specific array object by identifying thr parentActivityId.Any help will be really appreciated.

回答1:

With a recursive proposal and Array.prototype.reduce():

var data=[{id:1,activityName:"Drilling",parentActivityId:0,items:[{id:2,activityName:"Blasting",parentActivityId:1,items:[{id:3,activityName:"Ann",parentActivityId:2,items:[]},{id:4,activityName:"Ann",parentActivityId:2,items:[]}]},{id:5,activityName:"Transport",parentActivityId:1,items:[{id:6,activityName:"Daniel",parentActivityId:5,items:[]}]}]}],
    child = { id: 7, activityName: "Drilling", parentActivityId: 1, items: [] };

function getParent(r, a) {
    return a.id === child.parentActivityId ? a : a.items.reduce(getParent, r);
}

var node = data.reduce(getParent, {});
'items' in node && node.items.push(child);

document.write('<pre>' + JSON.stringify(data, 0, 4) + '</pre>');

回答2:

You were close to what you tried to achieve. This should do the trick:

var arrObj = {
    id: 7,
    activityName: "Drilling",
    parentActivityId: 1,
    items: []
};

function populateObj(data, arrObj) {
   for (var i = 0; i < data.length; i++) {
        if (data[i].id == arrObj.parentActivityId) {
            data[i].items.push(arrObj);
        } else {
            populateObj(data[i].items, arrObj);
        }
    }
};

populateObj(arrObj);

回答3:

To check the objects inside items array as well,you can do something like this,

var objectList = [
        {
            id: 1,
            activityName: "Drilling",
            parentActivityId: 0,
            items: [
                {
                    id: 2,
                    activityName: "Blasting",
                    parentActivityId: 1,
                    items: [
                        {
                            id: 3,
                            activityName: "Ann",
                            parentActivityId: 2,
                            items: [],

                        },
                        {
                            id: 4,
                            activityName: "Ann",
                            parentActivityId: 2,
                            items: [],

                        },
                    {
                         id: 7,
                         activityName: "Drilling",
                         parentActivityId: 2,
                         items: [],
                     }
                    ]
                },
                {
                    id: 5,
                    activityName: "Transport",
                    parentActivityId: 1,
                    items: [
                        {
                            id: 6,
                            activityName: "Daniel",
                            parentActivityId: 5,
                            items: [],
                        }
                    ]
                }
            ]
        }
    ];

var arrObj = {
    id: 7,
    activityName: "Drilling",
    parentActivityId: 1,
    items: []
};

function populateObj(ItemList) {
   for (var i = 0; i < ItemList.length; i++) {
        if (ItemList[i].id == arrObj.parentActivityId) {
            ItemList[i].items.push(arrObj);
        }
       else
       {
         populateObj(ItemList[i].items);
       }
    }
};

populateObj(objectList);

来源：https://stackoverflow.com/questions/32092074/not-able-to-push-an-object-into-parent-array-by-identifying-the-parent-id-of-the