How to get keys (path to) the deepest nested object in a javascript nested object

Question

I have a nested javascript object like this:

{
    "apple": {
        "orange": {
            "chilli": {},
            "pineapple": {
                "mango": {}
            }
        },
        "carrot": {
            "cabbage": {},
            "onion": {}
        }
    }
}

i want to get the path (keys) of the deepest nested object. something like apple.orange.pineapple.mango

any help is appriciated :)

Answer 1

You could return an array of arrays with the longest pathes.

This works for more than one path with the same length.

function getDeepest(object) {
    return object && typeof object === 'object'
        ? Object.entries(object).reduce((r, [k, o]) => {
            var temp = getDeepest(o).reduce((r, a, i) => {
                    if (!i || r[0].length < a.length) return [a];
                    if (r[0].length === a.length) r.push(a);
                    return r;
                }, []);

            return temp.length
                ? [...r, ...temp.map(t => [k].concat(t))]
                : [...r, [k]];
        }, [])
        : [];
}

var object = { apple: { orange: { chilli: {}, pineapple: { mango: {} } }, carrot: { cabbage: {}, onion: {} } } };

console.log(getDeepest(object).map(a => a.join('.')));