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: Use a recursive function.
• Kd dev: @Bergi Thanks for your suggestion. I have tried but not working for me may be i am missing something.
• Bergi: Please edit your question to include the code you tried, otherwise we cannot help you find the problem with it.
• Kd dev: @Bergi i have included my code.
• Bergi: 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.

Answer 1

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"));

Answer 2

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"));

Answer 3

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' } ] }
*/

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Disclaimer: I'm the author of object-scan