Sort-Index from nested JSON with Javascript

Question

How can I recursively add a sort key to an infinite hierarchy like this:

[
    {
        "id": "D41F4D3D-EA9C-4A38-A504-4415086EFFF8",
        "name": "A",
        "parent_id": null,
        "sortNr": 1,
        "children": [
            {
                "id": "07E556EE-F66F-49B5-B5E4-54AFC6A4DD9F",
                "name": "A-C",
                "parent_id": "D41F4D3D-EA9C-4A38-A504-4415086EFFF8",
                "sortNr": 3,
                "children": []
            },
            {
                "id": "8C63981E-0D30-4244-94BE-658BAAF40EF3",
                "name": "A-A",
                "parent_id": "D41F4D3D-EA9C-4A38-A504-4415086EFFF8",
                "sortNr": 1,
                "children": [
                    {
                        "id": "0BA32F23-A2CD-4488-8868-40AD5E0D3F09",
                        "name": "A-A-A",
                        "parent_id": "8C63981E-0D30-4244-94BE-658BAAF40EF3",
                        "sortNr": 1,
                        "children": []
                    }
                ]
            },
            {
                "id": "17A07D6E-462F-4983-B308-7D0F6ADC5328",
                "name": "A-B",
                "parent_id": "D41F4D3D-EA9C-4A38-A504-4415086EFFF8",
                "sortNr": 2,
                "children": []
            }
        ]
    },
    {
        "id": "64535599-13F1-474C-98D0-67337562A621",
        "name": "B",
        "parent_id": null,
        "sortNr": 2,
        "children": []
    },
    {
        "id": "1CE38295-B933-4457-BBAB-F1B4A4AFC828",
        "name": "C",
        "parent_id": null,
        "sortNr": 3,
        "children": [
            {
                "id": "D1E02274-33AA-476E-BA31-A4E60438C23F",
                "name": "C-A",
                "parent_id": "1CE38295-B933-4457-BBAB-F1B4A4AFC828",
                "sortNr": 1,
                "children": [
                    {
                        "id": "76A8259C-650D-482B-91CE-D69D379EB759",
                        "name": "C-A-A",
                        "parent_id": "D1E02274-33AA-476E-BA31-A4E60438C23F",
                        "sortNr": 1,
                        "children": []
                    }
                ]
            }
        ]
    }
]

I want to get a sortable index. For example 0000.0001.0003 or 0001.0003 for node A-C.

The function for leadingZeroes is

function fillZeroes (num) {
    var result = ('0000'+num).slice(-4);
    if (num===null){
       return result
    } else {
    return '0000';
    }
}

It should be sorted by sort number in each level of hierarchy, the sort number should be set newly every time, because I want to do rearrangement by setting it 1,5 to insert it between 1 and 2 (later for drag and drop capability). so 1;1,5;2 should become 1;2;3 and can then be translated to a sort-index like above.

I will also need it for indentation and breadcrumb-stuff.

How do I insert the proper sort-index to each object ?

The question is mainly about the recursion part. I am quite new to JavaScript

Thanks a lot

possible duplicate of stackoverflow.com/questions/26415675/… — Shoukat Mirza
– Shoukat Mirza, Commented Nov 20, 2018 at 12:09
Can you clarify about 1,5 - you mean that sortNr property could be floating point number? — Daniil Andreyevich Baunov
– Daniil Andreyevich Baunov, Commented Nov 20, 2018 at 12:29
@DaniilAndreyevichBaunov exactly. If there's just support for integers in JSON I would go with 2,4,6 as representations for 1,2,3 and "insert" with odd numbers. — nch68
– nch68, Commented Nov 20, 2018 at 12:35
@nch68, I see. So, to summarize, as I understand, you want to base your sort index on sortNr property. And also make it dense so that e.g. sortNr of 1, 5, 5.5, 6 within a single level will become something like 0001, 0002, 0003, 0004. Is it correct? Btw, the answer @georg has given is pretty need. Just needs some adjustment for your use case. — Daniil Andreyevich Baunov
– Daniil Andreyevich Baunov, Commented Nov 20, 2018 at 12:38

Daniil Andreyevich Baunov · Accepted Answer · 2018-11-20 13:18:59Z

1

Based on great answer by @georg. A bit adjusted solution based on sortNr object property. You can run it straight as is with json being your object. The sort index is written into sortOrder property.

// Mutates the given object in-place.
// Assigns sortOrder property to each nested object
const indexJson = (json) => {

  const obj = {children: json};

  const format = (xs) => xs.map(x => pad(x, 4)).join('.');
  const pad = (x, w) => (10 ** w + x).toString().slice(-w);

  const renumber = (obj, path) => {
    obj.path = path;
    obj.sortOrder = format(path);
    obj.children.slice()
      .sort((obj1, obj2) => obj1.sortNr - obj2.sortNr)
      .forEach((c, n) => renumber(c, path.concat(n+1)));
  };

  renumber(obj, []);
};

indexJson(json);

console.log(JSON.stringify(json, null, 2));

edited Nov 20, 2018 at 13:18

answered Nov 20, 2018 at 13:02

Daniil Andreyevich Baunov

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2 Comments

Daniil Andreyevich Baunov Over a year ago

@nch68, please upvote the answer if it is helpful. This works as a thanks here.

nch68 Over a year ago

I can't because I have less than "15 reputation" :/

georg · Accepted Answer · 2018-11-20 15:53:45Z

1

Basically

let renumber = (obj, path) => {
    obj.path = path
    obj.children.forEach((c, n) => renumber(c, path.concat(n)))
}

renumber({children: yourData}, [])

this creates a path property, which is an array of relative numbers. If you want to format it in a special way, then you can do

obj.path = format(path)

where format is like

let format = xs => xs.map(pad(4)).join(',')

let pad = w => x => (10 ** w + x).toString().slice(-w)

edited Nov 20, 2018 at 15:53

answered Nov 20, 2018 at 12:28

georg

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