Iterating through nested object arrays

I have a hierarchical tree

const graph = {
  value: 65, children: [{
    value: 15,
    children: [{
      value: 55,
      children: [{
        value: 85,
        children: [{
          value: 66,
          children: [{ value: 29 }, { value: 21 }]
        }]
      }]
    }]
  }]
};

How can i, for examle, find the node with max value, using map(), reduce() ?