sql.js-as-sqlite3

A wrapper around sql.js (a web-browser version of SQLite) that exposes the same API interface as sqlite3 connected to a normal SQLite database.

Demo

Why?

sequelize is an ORM that supports many databases, including SQLite, which is written in C++. Specifically, sequelize uses sqlite3 package to "talk" to SQLite. Both SQLite and sqlite3 package were written in C++ and weren't originally designed to work in a web browser.

Then appeared an unofficial port of SQLite to WASM (web-browser-compatible code) called sql.js. Because sqlite3 is not designed to work in a web browser, it won't support this sql.js web-browser-compatible port. And because sequelize relies exclusively on sqlite3 when working with SQLite, it won't support sql.js either.

But there's a loophole in sequelize — specifically, a dialectModule parameter — that allows swapping the sqlite3 module with any arbitrary one so long as it keeps the same "interface".

So the workaround is to create a wrapper around sql.js so that for sequelize it becomes indistinguishable from sqlite3, effectively tricking sequelize into thinking that it still works with SQLite over sqlite3 in Node.js instead of actually working with sql.js in a web browser.

And this is all that sql.js-as-sqlite3 package does.

Install

npm install sql.js sql.js-as-sqlite3 --save

If you're not using a "bundler" then use a standalone version from a CDN.

Use

Node.js

import sqlite3 from 'sql.js-as-sqlite3'

// Use it as if it was `sqlite3`
const db = new sqlite3.Database(':memory:')

Browser (with bundler)

import sqlJsAsSqlite3 from 'sql.js-as-sqlite3'
import initSqlJs from 'sql.js'

sqlJsAsSqlite3.configure({
  // `sql.js` package default export.
  initSqlJs,
  // Base URL for `sql.js` to get the `*.wasm` files like `sql-wasm-debug.wasm`.
  // The version of the `*.wasm` files must match the version of the `sql.js` package.
  // Must end with a "/".
  wasmFileBaseUrl: 'https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.10.2/'
})

// Use it as if it was `sqlite3`
const db = new sqlite3.Database(':memory:')

Browser (no bundler)

When not using a "bundler", one can import the package in a web browser by including it from a CDN such as unpkg.com or jsdelivr.com

<script src="https://unpkg.com/[email protected]/bundle/sql.js-as-sqlite3.min.js"></script>

<script src="https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.10.2/sql-wasm.min.js"></script>
<script>
  // Base URL for `sql.js` to get the `*.wasm` files like `sql-wasm-debug.wasm`.
  // The version of the `*.wasm` files must match the version of `sql.js`.
  // Must end with a "/".
  SQL_JS_WASM_FILE_BASE_URL = 'https://cdnjs.cloudflare.com/ajax/libs/sql.js/1.10.2/'
</script>

<script>
  // Use it as if it was `sqlite3`
  const db = new sqlJsAsSqlite3.Database(':memory:')
</script>

Sequelize

This package could be used to make sequelize ORM work with sql.js (a port of SQLite database that works in a web browser):

import Sequelize from 'sequelize'
import sqlite3 from 'sql.js-as-sqlite3'

const sequelize = new Sequelize('sqlite://:memory:', {
  dialectModule: sqlite3
})

For a server-side example, see a test.

For a client-side example, see sequelize-browser package.

Notes

In April 2023, SQLite released an official WASM-compatible npm package intended to be used in a web browser. It could be viewed as an "official" alternative to sql.js which was itself released in late 2016 and is still maintained as of early 2026. Which one is "better" for web-browser use? I personally don't really bother to care. I guess sql.js author could come up with a benchmark or a readme comparison section.

References

Based on the code by @domasx2.

GitHub

On March 9th, 2020, GitHub, Inc. silently banned my account (erasing all my repos, issues and comments, even in my employer's private repos) without any notice or explanation. Because of that, all source codes had to be promptly moved to GitLab. The GitHub repo is now only used as a backup (you can star the repo there too), and the primary repo is now the GitLab one. Issues can be reported in any repo.

License

MIT