Connect to Turso Cloud from TypeScript/JavaScript, including edge and serverless runtimes

Documented steps

1. Pick the package for your runtime (https://docs.turso.tech/sdk/ts/reference): @tursodatabase/serverless for remote-only, fetch-based access with no native dependencies; @libsql/client for remote plus embedded replicas; @tursodatabase/sync for local database with explicit push/pull.
2. Serverless/edge: `npm i @tursodatabase/serverless`, then `import { connect } from '@tursodatabase/serverless'; const conn = connect({ url: process.env.TURSO_DATABASE_URL, authToken: process.env.TURSO_AUTH_TOKEN });`.
3. Node/long-lived process: `npm i @libsql/client`, then `import { createClient } from '@libsql/client'; const client = createClient({ url, authToken });`.
4. Set TURSO_DATABASE_URL from `turso db show <db> --url` and TURSO_AUTH_TOKEN from `turso db tokens create <db>`.
5. Always use bound parameters: `client.execute({ sql: 'SELECT * FROM users WHERE id = ?', args: [id] })`.
6. For multiple statements that must succeed together, use `client.batch([...], 'write')` — it wraps them in one implicit all-or-nothing transaction.
7. For read/modify/write logic, use `const tx = await client.transaction('write')` then execute/commit/rollback, and always close it in a finally block.
8. Create the client once per process (module scope), not per request, so connection reuse and the client's internal concurrency limit apply.