Traverse the values of an object

traverse.js

function traverse(obj, callback) {
    const stack = [];
    stack.push(obj);

    while (stack.length) {
        const current = stack[0];

        for (const key of Object.keys(current)) {
            if (current[key] != null && typeof current[key] === 'object') {
                stack.push(current[key]);
                continue;
            } 

            callback(key, current[key], current);
        }

        stack.shift();
    }
}