create a tree from list

listToTree.ts

type BaseObj = {
  id: string;
  parentId: string | null;
};

type Result<T extends BaseObj> = T & {
  children: Result<T>[];
};
export const listToTree = (
  arr: BaseObj[],
  parentId: string | null = null,
  resolveId = ({ id }: BaseObj) => id,
  resolveParent = ({ parentId }: BaseObj) => parentId
) => {
  const out: Result<BaseObj>[] = [];
  for (const i in arr) {
    if (resolveParent(arr[i]) === parentId) {
      const children = listToTree(arr, resolveId(arr[i]));

      const { id, parentId, ...omit } = arr[i];
      const res: Result<BaseObj> = {
        id,
        parentId,
        children: [],
      };

      res.children = children || [];
      out.push(res);
    }
  }
  return out;
};