Collecting all node values of the tree

It is required to implement the function collectValues, which returns an array with the values of all nodes of the given tree.

const root = {
  value: 1,
  children: [
    {
      value: 2,
      children: [
        { value: 4 },
        { value: 5 },
      ],
    },
    {
      value: 3,
      children: [
        { value: 6 },
        { value: 7 },
      ],
    },
  ],
};

collectValues(root); // => [1, 2, 3, 4, 5, 6, 7]