JavaScript: Target a given value in a nested JSON object

JavaScript fundamental (ES6 Syntax): Exercise-6 with Solution

Write a JavaScript program to target a given value in a nested JSON object, based on the given key.

  • Use the in operator to check if target exists in obj.
  • If found, return the value of obj[target].
  • Otherwise use Object.values(obj) and Array.prototype.reduce() to recursively call dig on each nested object until the first matching key/value pair is found.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2
const dig = (obj, target) =>
  target in obj
    ? obj[target]
    : Object.values(obj).reduce((acc, val) => {
        if (acc !== undefined) return acc;
        if (typeof val === 'object') return dig(val, target);
      }, undefined);

const data = {
  level1: {
    level2: {
      level3: 'some data'

const dog = {
    "status": "success",
    "message": "https://images.dog.ceo/breeds/african/n02116738_1105.jpg"
console.log(dig(data, 'level3'));
console.log(dig(data, 'level4'));
console.log(dig(dog, 'message'));

Sample Output:

some data


flowchart: Target a given value in a nested JSON object

Live Demo:

See the Pen javascript-basic-exercise-1-6 by w3resource (@w3resource) on CodePen.

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Next: Write a JavaScript program to converts a specified number to an array of digits.

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JavaScript: Tips of the Day

How to remove a specific item from an array?

Find the index of the array element you want to remove using indexOf, and then remove that index with splice.

The splice() method changes the contents of an array by removing existing elements and/or adding new elements.

const array = [2, 5, 9];


const index = array.indexOf(5);
if (index > -1) {
  array.splice(index, 1);

// array = [2, 9]

The second parameter of splice is the number of elements to remove. Note that splice modifies the array in place and returns a new array containing the elements that have been removed.

For the reason of completeness, here are functions. The first function removes only a single occurrence (i.e. removing the first match of 5 from [2,5,9,1,5,8,5]), while the second function removes all occurrences:

function removeItemOnce(arr, value) {
  var index = arr.indexOf(value);
  if (index > -1) {
    arr.splice(index, 1);
  return arr;

function removeItemAll(arr, value) {
  var i = 0;
  while (i < arr.length) {
    if (arr[i] === value) {
      arr.splice(i, 1);
    } else {
  return arr;
console.log(removeItemOnce([2,5,9,1,5,8,5], 5))
console.log(removeItemAll([2,5,9,1,5,8,5], 5))

Ref: https://bit.ly/2N9nKRp