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:

Live Demo:

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

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