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

dig

Returns 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(obj) and Array.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