Find object by specific key in a deep nested object | Javascript

Question

What is the cleanest way to find object and return that based on id , If I don't know how many nested object there will be in my object ?

Let's say I have the following structure :

  myObj = {
              "id": "5e6b8961ba08180001a10bb6",
              "children": [
                {
                  "id": "5e6b8961ba08180001a10bb7",
                  "refrenceId": "SEC-02986",
                  "children": [
                    {
                      "id": "5e58d7bc1bbc71000118c0dc"
                    },
                    {
                      "id": "5e58d7bc1bbc71000118c0dd",
                      "refrenceId": "SKU-00343"
                     },
                    {
                      "id": "5e590d571bbc71000118c102",
                      "refrenceId": "SKU-05290"
                    },
                    {
                      "id": "5e590df71bbc71000118c109",
                      "children": [
                        {
                          "id": "5e590df71bbc71000118c10a"
                        },
                        {
                          "id": "5e590df71bbc71000118c10b",
                          "refrenceId": "SKU-00444"
                    },
                    {
                      "id": "5e5cb9428ae591000177c0f6"
                    }
                  ]
                },
                {
                  "id": "5e81899f0bab450001dcfc1d",
                  "refrenceId": "SEC-03260"
                },
                {
                  "id": "5e81c4b51503860001f97f6c",
                  "refrenceId": "SEC-03267",
                  "children": [
                    {
                      "id": "5e8ad5175d374200014edb3a",
                      "refrenceId": "SEC-03409",
                      "children": [
                        {
                          "id": "5e8f28882d94c1000156bebe"
                        }
                      ]
                    },
                    {
                      "id": "5e8ad5175d374200014edb3c",
                       "refrenceId": "SEC-03410"
                    },
                    {
                      "id": "5e8f29082d94c1000156bec6",
                      "refrenceId": "SEC-03495"
                    }
                  ]
                }
              ]
            }

Suppose, I want to find the one with id "5e590df71bbc71000118c10b", and return that object from nested object.

I have tried using following code:

   function nodeHasChildren(children, id) {

    for (const child of children) {

      if (child.id === id) {

        if (Array.isArray(child.children) && child.children.length > 0) {
          return child;
        }
      }
      else {
          const result = nodeHasChildren(child.children, id);

        if (result !== undefined) {
          return result
        }
      }
    }
  }

console.log(nodeWithIdHasChildren(myObj, "5e590df71bbc71000118c10b"));

@Bergi Thanks for your suggestion. I have tried but not working for me may be i am missing something. — Kd dev
– Kd dev, Commented Apr 15, 2020 at 14:54
Please edit your question to include the code you tried, otherwise we cannot help you find the problem with it. — Bergi
– Bergi, Commented Apr 15, 2020 at 14:55
You'll want to return the child, not its children, I suppose? The tests for testing whether the child has children are superflous then. If you remove these if statements, the scope of result will be correct as well. — Bergi
– Bergi, Commented Apr 15, 2020 at 15:06

Gabriele Petrioli · Accepted Answer · 2020-04-15 15:21:29Z

Use simple recursion

function findDeepById(node, id) {
  if (node.id === id) return node;
  if (node.children) {
    for(const child of node.children){
      const match = findDeepById(child, id);
      if (match) return match;
    }
  }
}

const myObj = {
  "id": "5e6b8961ba08180001a10bb6",
  "children": [{
    "id": "5e6b8961ba08180001a10bb7",
    "refrenceId": "SEC-02986",
    "children": [{
        "id": "5e58d7bc1bbc71000118c0dc"
      },
      {
        "id": "5e58d7bc1bbc71000118c0dd",
        "refrenceId": "SKU-00343"
      },
      {
        "id": "5e590d571bbc71000118c102",
        "refrenceId": "SKU-05290"
      },
      {
        "id": "5e590df71bbc71000118c109",
        "children": [{
            "id": "5e590df71bbc71000118c10a"
          },
          {
            "id": "5e590df71bbc71000118c10b",
            "refrenceId": "SKU-00444"
          },
          {
            "id": "5e5cb9428ae591000177c0f6"
          }
        ]
      },
      {
        "id": "5e81899f0bab450001dcfc1d",
        "refrenceId": "SEC-03260"
      },
      {
        "id": "5e81c4b51503860001f97f6c",
        "refrenceId": "SEC-03267",
        "children": [{
            "id": "5e8ad5175d374200014edb3a",
            "refrenceId": "SEC-03409",
            "children": [{
              "id": "5e8f28882d94c1000156bebe"
            }]
          },
          {
            "id": "5e8ad5175d374200014edb3c",
            "refrenceId": "SEC-03410"
          },
          {
            "id": "5e8f29082d94c1000156bec6",
            "refrenceId": "SEC-03495"
          }
        ]
      }
    ]
  }]
};

function findDeepById(node, id) {

  if (node.id === id) return node;
  if (node.children) {
    for(const child of node.children){
      const match = findDeepById(child, id);
      if (match) return match;
    }
  }
}

console.log(findDeepById(myObj, "5e590df71bbc71000118c10b"));

Shomz · Accepted Answer · 2020-04-15 15:31:14Z

In short, this part was the biggest problem:

if (child.id === id) {

    if (Array.isArray(child.children) && child.children.length > 0) {
      return child;
    }
  }

You've found your object, why look for its children?

ORIGINAL ANSWER/WORKING SOLUTION

For start, you need to make your original object iterable because that's what your function expects, I've done so by simply making it an array like nodeHasChildren([myObj], ... when calling the function. Then, after some cleanup and fixing the logic mentioned above, we get this (added relevant comments to the code below):

myObj = {
  "id": "5e6b8961ba08180001a10bb6",
  "children": [{
    "id": "5e6b8961ba08180001a10bb7",
    "refrenceId": "SEC-02986",
    "children": [{
        "id": "5e58d7bc1bbc71000118c0dc"
      },
      {
        "id": "5e58d7bc1bbc71000118c0dd",
        "refrenceId": "SKU-00343"
      },
      {
        "id": "5e590d571bbc71000118c102",
        "refrenceId": "SKU-05290"
      },
      {
        "id": "5e590df71bbc71000118c109",
        "children": [{
            "id": "5e590df71bbc71000118c10a"
          },
          {
            "id": "5e590df71bbc71000118c10b",
            "refrenceId": "SKU-00444"
          },
          {
            "id": "5e5cb9428ae591000177c0f6"
          }
        ]
      },
      {
        "id": "5e81899f0bab450001dcfc1d",
        "refrenceId": "SEC-03260"
      },
      {
        "id": "5e81c4b51503860001f97f6c",
        "refrenceId": "SEC-03267",
        "children": [{
            "id": "5e8ad5175d374200014edb3a",
            "refrenceId": "SEC-03409",
            "children": [{
              "id": "5e8f28882d94c1000156bebe"
            }]
          },
          {
            "id": "5e8ad5175d374200014edb3c",
            "refrenceId": "SEC-03410"
          },
          {
            "id": "5e8f29082d94c1000156bec6",
            "refrenceId": "SEC-03495"
          }
        ]
      }
    ]
  }]
}


function nodeHasChildren(children, id) {
  for (const child of children) {
    if (child.id === id) { 
          // solution found, no need to do anything else
          console.log("SOLUTION: ");
          return child;
    } else {
      // check if it has children and iterate over them recursively
      if (Array.isArray(child.children) && child.children.length > 0)
        var result = nodeHasChildren(child.children, id);
      // check if the result was found in children in the line above
      if (result != undefined)
        return result;
    }
  }
}
console.log(nodeHasChildren([myObj], "5e590df71bbc71000118c10b"));
console.log(nodeHasChildren([myObj], "5e8ad5175d374200014edb3c"));

vincent · Accepted Answer · 2021-01-19 01:33:59Z

We now use object-scan for simple data processing tasks. It's pretty awesome once you wrap your head around it. Here is how you could answer your questions

// const objectScan = require('object-scan');

const find = (id, input) => objectScan(['**'], {
  rtn: 'value',
  abort: true,
  filterFn: ({ value }) => value.id === id
})(input);

const myObj = { id: '5e6b8961ba08180001a10bb6', children: [{ id: '5e6b8961ba08180001a10bb7', refrenceId: 'SEC-02986', children: [{ id: '5e58d7bc1bbc71000118c0dc' }, { id: '5e58d7bc1bbc71000118c0dd', refrenceId: 'SKU-00343' }, { id: '5e590d571bbc71000118c102', refrenceId: 'SKU-05290' }, { id: '5e590df71bbc71000118c109', children: [{ id: '5e590df71bbc71000118c10a' }, { id: '5e590df71bbc71000118c10b', refrenceId: 'SKU-00444' }, { id: '5e5cb9428ae591000177c0f6' }] }, { id: '5e81899f0bab450001dcfc1d', refrenceId: 'SEC-03260' }, { id: '5e81c4b51503860001f97f6c', refrenceId: 'SEC-03267', children: [{ id: '5e8ad5175d374200014edb3a', refrenceId: 'SEC-03409', children: [{ id: '5e8f28882d94c1000156bebe' }] }, { id: '5e8ad5175d374200014edb3c', refrenceId: 'SEC-03410' }, { id: '5e8f29082d94c1000156bec6', refrenceId: 'SEC-03495' }] }] }] };

console.log(find('5e8ad5175d374200014edb3a', myObj));
/* =>
{ id: '5e8ad5175d374200014edb3a',
  refrenceId: 'SEC-03409',
  children: [ { id: '5e8f28882d94c1000156bebe' } ] }
*/

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

<script src="https://bundle.run/[email protected]"></script>

Disclaimer: I'm the author of object-scan

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