w3resource

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
undefined
https://images.dog.ceo/breeds/african/n02116738_1105.jpg

Flowchart:

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.


Improve this sample solution and post your code through Disqus

Previous: Write a JavaScript program to convert an array of objects to a comma-separated values (CSV) string that contains only the columns specified.
Next: Write a JavaScript program to converts a specified number to an array of digits.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Follow us on Facebook and Twitter for latest update.