How to add item to each level of a nested array

Question

I have infinite levels array in each object and I want to add "id" based on levels. Suppose if level 1 then id should be 1 and level two then id will be 2 etc.

{
"name": "Anything2",
"code": "SS_1",
"levels": [
    {
        "levelName": "New level",
        "levels": [
            {
                "levelName": "New Level2",
                "levels": [
                    {
                        "levelName": "New Level2",
                        {
                            "levelName": "New Level2",
                            "levels": [
                                {
                                    "levelName": "New level"
                                }
                            ]
                        }
                    },
                    {
                        "levelName": "New Level2",
                    },
                    {
                        "levelName": "New Level2",
                    }
                ]
            },
            {
                "levelName": "New Level2"
            },
            {
                "levelName": "New Level2",
                "levels": [
                    {
                        "levelName": "New level"
                    }
                ]
            }
        ]
    }
]

}

I want to convert the above array into below new array. I have tried using for loop but its not working I am not getting expected data. I want to add "id" based on levels. Suppose if level 1 then id should be 1 and level two then id will be 2 etc.

{
"name": "Anything2",
"code": "SS_1",
"levels": [
    {
        "level": 1,
        "levelName": "New level",
        "levels": [
            {
                "level": 2,
                "levelName": "New Level2",
                "levels": [
                    {
                        "level": 3,
                        "levelName": "New Level2",
                        {
                            "levelName": "New Level2",
                            "levels": [
                                {
                                    "level": 4,
                                    "levelName": "New level"
                                }
                            ]
                        }
                    },
                    {
                        "level": 3,
                        "levelName": "New Level2",
                    },
                    {
                        "level": 3,
                        "levelName": "New Level2",
                    }
                ]
            },
            {
                "level": 2,
                "levelName": "New Level2"
            },
            {
                "level": 2,
                "levelName": "New Level2",
                "levels": [
                    {
                        "level": 3,
                        "levelName": "New level"
                    }
                ]
            }
        ]
    }
]

}

Answer 1

You could take a recursive approach and hand over an incremented level for each level.

const
    addLevel = (level = 0) => ({ levels = [], ...o }) =>
        ({ level, ...o, levels: levels.map(addLevel(level + 1)) }),
    data = ...,
    result = addLevel()(data);

Answer 2

Here I call the property "depth":

 const data = { "name": "Anything2", "code": "SS_1", "levels": [{ "levelName": "New level", "levels": [{ "levelName": "New Level2", "levels": [{ "levelName": "New Level2" }, { "levelName": "New Level2", "levels": [{ "levelName": "New level" }] }, { "levelName": "New Level2" }, { "levelName": "New Level2" } ] }, { "levelName": "New Level2" }, { "levelName": "New Level2", "levels": [{ "levelName": "New level" }] } ] }] }; function addleveldepth(arr, depth = 1) { arr.forEach(obj => { obj.depth = depth; if (obj.levels) { addleveldepth(obj.levels, depth + 1); } }); } addleveldepth(data.levels); console.log(data);

Answer 3

Think it works:

 const data = {"name": "Anything2","code": "SS_1","levels": [{"levelName": "New level","levels": [{"levelName": "New Level2","levels": [{"levelName": "New Level2","levels": [{"levelName": "New level"}]},{"levelName": "New Level2",},{"levelName": "New Level2",}]},{"levelName": "New Level2"},{"levelName": "New Level2","levels": [{"levelName": "New level"}]}]}]}; const iter = (arr, level) => arr.map((obj) => Array.isArray(obj.levels)? { level, ...obj, levels: iter(obj.levels, level + 1) }: { level, ...obj }); const result = {...data, levels: iter(data.levels, 1) }; console.dir(result, {depth: null})

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Answer 4

Here is a simple solution using a stack and a while loop.

 var tree = { children: [{ children: [{ children: [] }, { children: [] }] }, { children: [{ children: [] }] }] }; var stack = [ [tree, 0] // `0` is the `i` below ]; var n; while (n = stack.length) { let [node, i] = stack[n - 1]; if (i < node.children.length) { stack.push([node.children[i], 0]); stack[n - 1][1]++; // increment `i` } else { stack.pop(); node.depth = n; } } console.log(tree);