pglite with pgvector example code with file dump/load

main.js

import { PGlite } from "@electric-sql/pglite";
import { vector } from '@electric-sql/pglite/vector';
import fs from 'node:fs/promises';
import { createReadStream } from "node:fs";
import zlib from 'node:zlib';
import { pipeline } from 'node:stream/promises';

const pg = new PGlite({
  extensions: { vector },
});

await pg.sql`CREATE EXTENSION IF NOT EXISTS vector`;
// init the database
await pg.sql`CREATE TABLE IF NOT EXISTS items (id bigserial PRIMARY KEY, embedding vector(3))`;
await pg.sql`CREATE INDEX ON items USING hnsw (embedding vector_cosine_ops)`;
//await pg.sql`INSERT INTO items (embedding) VALUES ('[1, 2, 3]')`;

// insert random 
for (let i = 0; i < 1000; i++) {
  await pg.sql`INSERT INTO items (embedding) VALUES (${`[${Math.random()}, ${Math.random()}, ${Math.random()}]`})`;
}

// query the database
await fs.writeFile('foo.gz', (await pg.dumpDataDir('gzip')).stream());

const q = `[${Math.random()}, ${Math.random()}, ${Math.random()}]`
console.log(await pg.sql`SELECT * FROM items ORDER BY embedding <-> ${q} LIMIT 10`);

// another instance
await pg.close();

const chunks = [];
await pipeline(
    createReadStream('foo.gz'),
    zlib.createGunzip(),
    async function* (source) {
        for await (const chunk of source) {
            chunks.push(chunk);
        }
    }
)

const pg2 = new PGlite({
    extensions: { vector },
    loadDataDir: new Blob(chunks),
});

console.log(await pg2.sql`SELECT * FROM items ORDER BY embedding <-> ${q} LIMIT 10`);