Index folderName by parent_id

frontend/scratch/data_transfer.ts

@@ -4,10 +4,27 @@ import {
   RootFolderNode
 } from "./constants";
 
-type X = Record
+type NodeName = Required<FlatNodeName>;
+type NodeNameIndex = Record<number, NodeName[]>;
+
+const z: Readonly<NodeNameIndex> = {};
+
+const mapper =
+  (x: FlatNodeName): NodeName => ({ ...x, parent_id: x.parent_id || -1 });
+
+const reducer = (accum: NodeNameIndex, item: NodeName): NodeNameIndex => {
+  const { parent_id } = item;
+  const list = (accum[parent_id] || []);
+
+  return { ...accum, [parent_id]: [...list, item] };
+};
+
 export function ingest(_folders: FlatNode[], names: FlatNodeName[]): RootFolderNode {
   const output = { folders: [] };
-  const y = names
-    .map((x: FlatNodeName): Required<FlatNodeName> => ({ ...x, parent_id: x.parent_id || -1 }));
+  // const nameIndex =
+  names.map(mapper).reduce(reducer, z);
+  // const keys: keyof typeof nameIndex =
+  //   Object.keys(nameIndex).map(x => parseInt(x, 10)).sort();
+  // keys.
   return output;
 }