Nestable - how to iterate over JSON to build a hierarchy?

Question

JSON

Here is the JSON:

[{"id":2},{"id":3,"children":[{"id":5},{"id":6},{"id":7}]},{"id ":8,"children":[{"id":9},{"id":10}]},{"id":12,"children":[{"id":14}]},{ "id":13},{"id":15}]

How to make this JSON build a hierarchy in PHP?