node:sqlite

node-sqlite.ts

import { DatabaseSync } from "node:sqlite";

export class Fetcher {
  private database: DatabaseSync;

  constructor() {
    this.database = new DatabaseSync('cache.db', { open: true });
    this.database.exec(`
      CREATE TABLE IF NOT EXISTS cache (
        uri TEXT PRIMARY KEY,
        body TEXT
      ) STRICT;
    `);
  }

  async get(uri: string) {
    const query = this.database.prepare("SELECT body FROM cache WHERE uri = ?");
    const res = query.get(uri) as { body: string } | undefined;
    let body = res?.body ?? null;
    if (body == null) {
      body = await fetch(uri).then((res) => res.text());
      if (body == null) throw new Error(`Failed to fetch ${uri}`);
      this.database
        .prepare("INSERT INTO cache (uri, body) VALUES (?, ?)")
        .run(uri, body);
    }

    return body;
  }
}

nodemon.json

{
    "ext": ".ts",
    "exec": "node --experimental-strip-types --experimental-sqlite --disable-warning=ExperimentalWarning"
}