Solid-js tree store

Tree.tsx

import { render } from "solid-js/web";
import { createSignal, For, Show } from "solid-js";
import { createStore } from "solid-js/store";

const [state, setState] = createStore<TreeNode[]>([
  {
    value: "foo",
    children: [
      { value: "bar", children: [] },
      { value: "baz", children: [{ value: "quux", children: [] }] },
    ],
  },
  {
    value: "foo2",
    children: [
      { value: "bar", children: [] },
      { value: "baz", children: [{ value: "quux", children: [] }] },
    ],
  },
]);

interface TreeNode {
  value: string;
  selected?: boolean;
  children: TreeNode[];
}

interface TreeProps {
  nodes: TreeNode[];
  basePath: string;
  index: number[];
}

function* intersperse<T, R>(a: Array<T>, delim: R): Generator<T | R> {
  let first = true;
  for (const x of a) {
    if (!first) yield delim;
    first = false;
    yield x;
  }
}

const path = (basePath: string, value: string) => basePath + "/" + value;
const index = (baseIndex: number[], index: number) => [...baseIndex, index];
const treePath = (index: number[]): Array<number | "children"> =>
  [...intersperse(index, "children")] as Array<number | "children">;

function Tree(props: TreeProps) {
  const onClick = (node: TreeNode, idx: number) => {
    const p = path(props.basePath, node.value);
    const i = index(props.index, idx);
    const tp = treePath(i);
    console.log(p, i, tp);
    let ss: any = setState;
    ss(...tp, "selected", (s: any) => !!!s);
  };

  return (
    <ul>
      <For each={props.nodes}>
        {(node, i) => (
          <li>
            <button onClick={() => onClick(node, i())}>
              {path(props.basePath, node.value)}
              {node.selected ? " selected" : ""}
            </button>
            <Tree
              nodes={node.children}
              basePath={path(props.basePath, node.value)}
              index={[...props.index, i()]}
            />
          </li>
        )}
      </For>
    </ul>
  );
}

render(
  () => <Tree nodes={state} basePath="" index={[]} />,
  document.getElementById("app")!
);