const tree = {
  id: 1,
  name: "App",
  children: [
    {
      id: 2,
      name: "Header",
      children: [
        { id: 3, name: "Logo" },
        { id: 4, name: "Nav" }
      ]
    },
    {
      id: 5,
      name: "Content",
      children: [
        { id: 6, name: "Sidebar" },
        {
          id: 7,
          name: "Main",
          children: [{ id: 8, name: "Article" }]
        }
      ]
    }
  ]
};
//output
// {
//   1: "App",
//   2: "App > Header",
//   3: "App > Header > Logo",
//   4: "App > Header > Nav",
//   5: "App > Content",
//   6: "App > Content > Sidebar",
//   7: "App > Content > Main",
//   8: "App > Content > Main > Article"
// }


const formatter = (node, path = "", res={}) => {
    res[node.id] = path? path + ">" + node.name:node.name
    if(node.children) {
        node.children.forEach(item=>{
            formatter(item, res[node.id], res)
        })

    }
    return res
 
};
console.log(formatter(tree))