Cloudflare env emulator

cloudflareLocal.ts

/**
 * cloudflare local emulator
 */
import { parse } from "@iarna/toml";

type WranglerConfig = {
  d1_databases?: Array<{
    database_name: string;
    database_id: string;
    binding: string;
    migrations_dir: string;
  }>;
};

let _env: Record<string, any> | undefined = undefined;
export async function createCloudflareEnv() {
  if (!import.meta.env.DEV) throw new Error("DEV ONLY");
  if (_env) return _env;
  if (import.meta.env.DEV) {
    const env: Record<string, any> = {};
    const { default: raw } = await import("../../wrangler.toml?raw");
    const parsed = parse(raw) as WranglerConfig;
    for (const database of parsed.d1_databases ?? []) {
      env[database.binding] = await createD1(database.database_id);
    }
    return (_env = env);
  }
  throw new Error("Unreachable");
}

async function createD1(database_id: string) {
  const { D1DatabaseAPI, D1Database } = await import("@miniflare/d1");
  const { createSQLiteDB } = await import("@miniflare/shared");
  const db = await createSQLiteDB(
    `.wrangler/state/v3/d1/${database_id}/db.sqlite`,
  );
  return new D1Database(new D1DatabaseAPI(db));
}