Get parent, grandparent and key in the deep nested object structure

I have a deeply nested structure in the javascript object without any arrays in it.

var data = {
  bar: 'a',
  child: {
    b: 'b',
    grand: {
      greatgrand: {
        c: 'c'
      }
    }
  }
};

let arr = [];

const findParentGrandparent = (obj, target) => {
  Object.entries(obj).forEach(child => {
    if (typeof child[1] === 'object') {
      findParentGrandparent(child[1]);
    }
  });
};
findParentGrandparent(data, 'c');

When I call the function with a target, I want to get the taget key itself, parent and grandparent. For example, if the target is ‘c’, arr should become

['c', 'greatgrand', 'grand', 'child'];

if target is ‘greatgrand’, it should become

['greatgrand', 'grand', 'child'];

Thanks

Answer

I did it using your recursive pattern, you can change the way it handle errors also, here I throw if there is no result.

var data = {
  bar: 'a',
  child: {
    b: 'b',
    grand: {
      greatgrand: {
        c: 'c'
      }
    }
  }
};

let arr = [];

const findParentGrandparent = (obj, target) => {
  for (const child of Object.entries(obj)) {
    if (typeof child[1] === 'object' && child[0] !== target) {
      const result = findParentGrandparent(child[1], target);
      return [...result, child[0]];
    } else if (child[0] === target) {
      return [child[0]];
    }
  };
  throw new Error("not found"); // If it goes there the object is not found, you can throw or return a specific flag, as you wish.
};

console.log(findParentGrandparent(data, 'c'));