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DuckDB

DuckDB works on Val Town, with only one small tweak! We're basically using DuckDB in the same way you'd use it with a browser - using the WASM package with its dependencies fetched from jsdelivr.

The only trick is to create the worker ourselves rather than using duckdb.createWorker. DuckDB's built-in createWorker method doesn't specify a worker type, which causes type to default to classic, and Deno (our runtime) doesn't support classic workers.

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import { fetch } from "https://esm.town/v/std/fetch";
export let duckdbExample = (async () => {
async function createWorker(url: string) {
const workerScript = await fetch(url);
const workerURL = URL.createObjectURL(await workerScript.blob());
return new Worker(workerURL, { type: "module" });
}
const duckdb = await import(
"https://cdn.jsdelivr.net/npm/@duckdb/duckdb-wasm@1.17.0/+esm"
);
const bundles = duckdb.getJsDelivrBundles();
const bundle = await duckdb.selectBundle(bundles);
const logger = new duckdb.ConsoleLogger();
const worker = await createWorker(bundle.mainWorker);
const db = new duckdb.AsyncDuckDB(logger, worker);
await db.instantiate(bundle.mainModule);
const c = await db.connect();
const res = await c.query(`SELECT * FROM generate_series(1, 100) t(v)`);
c.close();
db.terminate();
// DuckDB's toJSON unfortunately includes BigInts, and we can't serialize
// BigInts because they have no basic JSON representation. So,
// Translate them to ints.
return res.toArray().map((r) => {
const row = r.toJSON();
return JSON.parse(JSON.stringify(row, (k, v) => {
return typeof v === "bigint" ? +v.toString() : v;
}));
});
})();
October 23, 2023