How to convert flat multi-branch data to hierarchical JSON?

Question

[
  {
    \"id\": \"a\",
    \"pid\": \"a\",
    \"name\": \"AA\",
  },
  {
    \"id\": \"b\",
    \"pid\": \"a\",
    \"name\": \"BB\",
  },
  {
    \"id\": \"c\",
         


        

Answer 1

Influenced by the answer of Nina, this is my resolution just for the record.

function corrugate(data){
  var root = "";
  return data.reduce((t,o) => {
    	                       o.id === o.pid && (root = o.id);
  	                           t[o.id]  ? t[o.id].name = o.name
  	                                    : t[o.id] = {id: o.id, name: o.name};
  	                           t[o.pid] ? o.pid !== o.id ? t[o.pid].children.push(t[o.id])
  	                                                     : t[o.pid].children = t[o.pid].children || []
  	                                    : t[o.pid] = {id: o.pid, children: [t[o.id]]};
  	                           return t;
                              },{})[root];
}

var   data = [{ "id": "f", "pid": "b", "name": "F" },
              { "id": "e", "pid": "c", "name": "E" },
              { "id": "b", "pid": "a", "name": "B" },
              { "id": "d", "pid": "c", "name": "D" },
              { "id": "c", "pid": "b", "name": "C" },
              { "id": "a", "pid": "a", "name": "A" }
             ];
console.log(corrugate(data));