Sort entire nested object by property in JavaScript

Question

I would like to loop through a deeply nested object, and sort each level based on a property. In this case its id

Here's my object (there will me more levels, I just added 3 levels here for readability):

const myObj = [
  {
    id: 15,
    children: [
      {
        id: 9,
        children: [
          {
            id: 4,
            children: []
          },
          {
            id: 1,
            children: []
          }
        ]
      },
      {
        id: 4,
        children: [
          {
            id: 35,
            children: [
              {
                id: 12,
                children: []
              },
              {
                id: 8,
                children: []
              }
            ]
          },
          {
            id: 30,
            children: [],
          }
        ]
      },
    ]
  },
  {
    id: 2,
    children: [
      {
        id: 9,
        children: []
      },
      {
        id: 3,
        children: []
      },
    ]
  }
]

Here's the desired output:

const myObj = [
  {
    id: 2,
    children: [
      {
        id: 3,
        children: []
      },
      {
        id: 9,
        children: []
      }
    ]
  },
  {
    id: 15,
    children: [
      {
        id: 4,
        children: [
          {
            id: 30,
            children: [],
          },
          {
            id: 35,
            children: [
              {
                id: 8,
                children: []
              },
              {
                id: 12,
                children: []
              }
            ]
          },
        ]
      },
      {
        id: 9,
        children: [
          {
            id: 1,
            children: []
          },
          {
            id: 4,
            children: []
          }
        ]
      },
    ]
  }
]

And here's my attempt at sorting it:

const myObj = [{id:15,children:[{id:9,children:[{id:4,children:[]},{id:1,children:[]}]},{id:4,children:[{id:35,children:[{id:12,children:[]},{id:8,children:[]}]},{id:30,children:[],}]},]},{id:2,children:[{id:9,children:[]},{id:3,children:[]},]}]

function sortByOrderIndex(obj) {
  obj.sort((a, b) => (a.orderindex > b.orderindex) ? 1 : ((b.orderindex > a.orderindex) ? -1 : 0));

  return obj;
}

function sortNestedObj(obj) {
  sortByOrderIndex(obj);

  for (let i = 0; i < obj.length; i++) {
    const t = obj[i];

    if (t.children.length !== 0) {
      sortNestedObj(t.children);
    } else {
      return;
    }
  }
}

console.log(sortByOrderIndex(myObj))

I've created a function that sorts an object, and then tried to create another object that loops through each object that has children and sort those children using the first function. And if those children have children, then sort those and so forth until a child has no children.

adiga · Accepted Answer · 2019-03-19 06:54:51Z

4

You could recursively sort the array and it's object's children like this:

const myObj = [{id:15,children:[{id:9,children:[{id:4,children:[]},{id:1,children:[]}]},{id:4,children:[{id:35,children:[{id:12,children:[]},{id:8,children:[]}]},{id:30,children:[],}]},]},{id:2,children:[{id:9,children:[]},{id:3,children:[]},]}]

function sortArray(array) {
  array.sort((a, b) => a.id - b.id);
  array.forEach(a => {
    if (a.children && a.children.length > 0)
      sortArray(a.children)
  })
  return array;
}

console.log(sortArray(myObj))

answered Mar 19, 2019 at 6:54

adiga

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Comments

mplungjan · Accepted Answer · 2019-03-19 07:01:08Z

1

You can make a recursive sorting function:

const myObj = [{id:15,children:[{id:9,children:[{id:4,children:[]},{id:1,children:[]}]},{id:4,children:[{id:35,children:[{id:12,children:[]},{id:8,children:[]}]},{id:30,children:[],}]},]},{id:2,children:[{id:9,children:[]},{id:3,children:[]},]}]

const orderChildren = obj => {
  obj.children.sort((a, b) => a.id - b.id);
  if (obj.children.some(o => o.children.length)) {
    obj.children.forEach(child => orderChildren(child));
  }
  return obj;
};

const myNewObj = myObj.map(o => orderChildren(o)).sort((a, b) => a.id - b.id);

console.log(myNewObj);

.as-console-wrapper { max-height: 100% !important; top: 0; }

edited Mar 19, 2019 at 7:01

mplungjan

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answered Mar 19, 2019 at 6:55

Jack Bashford

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Comments

Yosvel Quintero · Accepted Answer · 2019-03-19 07:13:44Z

1

You can do:

const myObj = [{id: 15,children: [{id: 9,children: [{id: 4,children: []},{id: 1,children: []}]},{id: 4,children: [{id: 35,children: [{id: 12,children: []},{id: 8,children: []}]},{id: 30,children: [],}]},]},{id: 2,children: [{id: 9,children: []},{id: 3,children: []},]}];
const deepSortById = arr => (arr.forEach(a => a.children && deepSortById(a.children)), arr.sort((a, b) => a.id - b.id));

const result = deepSortById(myObj);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Mar 19, 2019 at 7:13

Yosvel Quintero

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Comments

michal.jakubeczy · Accepted Answer · 2021-07-07 09:11:02Z

0

I created generic solution for sorting nested arrays by id. My solution works with any nested array and sorts it according to id property. Or by any other property you specify in the method's seconds parameter.

function sortNestedArrays(obj, sortPropertyName) {
    Object.keys(obj).forEach((key) => {
        if (Array.isArray(obj[key])) {
            obj[key].sort((a, b) => a[sortPropertyName] - b[sortPropertyName]);
        }

        if (!!obj[key] && (typeof obj[key] === 'object' || Array.isArray(obj[key]))) {
            sortNestedArrays(obj[key], sortPropertyName);
        }
    });

    return obj;
}

Usage is following:

obj = sortNestedArrays(obj, 'id');

answered Jul 7, 2021 at 9:11

michal.jakubeczy

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