30-seconds-of-code/snippets/dig.md

title, tags, expertise, cover, firstSeen, lastUpdated

title	tags	expertise	cover	firstSeen	lastUpdated
Get nested value in object	object,recursion	intermediate	blog_images/brown-bird.jpg	2018-07-08T23:06:24+03:00	2020-10-19T18:51:03+03:00

Gets the target 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() and Array.prototype.reduce() to recursively call dig on each nested object until the first matching key/value pair is found.

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'
    }
  }
};
dig(data, 'level3'); // 'some data'
dig(data, 'level4'); // undefined