Search a complex object by id property in JavaScript

Suppose we have a complex JSON Object like this −

const obj = {    "id": "0001",    "fieldName": "sample1",    "fieldValue" "0001",    "subList": [       {          "id": 1001,          "fieldName": "Sample Child 1",          "fieldValue": "1001",          "subList": []       },       {          "id": 1002,          "fieldName": "Sample Child 2",          "fieldValue": "1002",          "subList": []       }    ] }

We are required to write a JavaScript function that takes in one such object and a key value pair (necessarily an "id" key-value pair). Then the function should return the whole sub object that contains the queried key/value pair.

Example

The code for this will be −

const obj = {    "id": "0001",    "fieldName": "sample1",    "fieldValue": "0001",    "subList": [       {          "id": 1001,          "fieldName": "Sample Child 1",          "fieldValue": "1001",          "subList": []       },       {          "id": 1002,          "fieldName": "Sample Child 2",          "fieldValue": "1002",          "subList": []       }    ] } function searchById(searchKey, obj) {    let key = Object.keys(searchKey)[0];    let res;    if (obj[key] === searchKey[key]) {       return obj;    };    obj.subList.some(function (a) {       res = searchById(searchKey, a);       return res;    });    return res; } console.log(searchById({id: 1002}, obj));

Output

And the output in the console will be −

{    id: 1002,    fieldName: 'Sample Child 2',    fieldValue: '1002',    subList: [] }