[feat] Move types to separate file

lib/notion.ts

 import { NOTION_KEY } from "../config";
+import { DatabaseType } from "../types";
 
 const { Client } = require("@notionhq/client");
 
 export const notion = new Client({ auth: NOTION_KEY });
 
-export type DatabaseType = "laws" | "advice";
-
 /**
  * Translates incoming GET parameters into a valid block ID.
  * @param type

pages/api/getTopicList.ts

 // Next.js API route support: https://nextjs.org/docs/api-routes/introduction
 import type { NextApiRequest, NextApiResponse } from "next";
-import { DatabaseType, getDatabaseId, notion } from "../../lib/notion";
-
-interface Topic {
-  blockId: string;
-  name: string;
-}
-
-interface Error {
-  status: string;
-}
+import { getDatabaseId, notion } from "../../lib/notion";
+import { DatabaseType, Error, Topic } from "../../types";
 
 function getTopicsInDatabase(notionResp: any): Topic[] {
   return notionResp.results.map((block: any) => ({

types.ts

+export type DatabaseType = "laws" | "advice";
+
+export interface Topic {
+  blockId: string;
+  name: string;
+}
+
+export interface Error {
+  status: string;
+}