Search JavaScript objects

search.js

function searchValue(needle, haystack, depth) {
  var recur;
  recur = (findVal, obj, path, res, depth) => {
    if (obj === findVal) {
      res.push(path);
    }
    if (depth === 0) {
      return;
    }
    if ('object' === typeof obj && obj !== null) {
      var keys = Object.keys(obj);
      keys.forEach((k) => recur(findVal, obj[k], path+'.'+k, res, depth-1));
    }
  };
  var res = [];
  recur(needle, haystack, 'root', res, depth);
  return res;
}

// Yields ["root.hello.data"]:
searchValue('hi', {hello: {data: 'hi', name: 'Joe'}}, 3);