This is a WebAssembly build of SQLite with experimental support for writing SQLite virtual filesystems and virtual table modules completely in Javascript. This allows alternative browser storage options such as IndexedDB.

An IndexedDB virtual filesystem and a virtual table module that accesses Javascript arrays are provided as proof of concept.

Try the demo with a modern desktop web browser.

The primary motivation for this project is to enable additions to SQLite with only Javascript. Most developers should be able to use the "buildless" branch with pre-built artifacts checked in. This is also recommended when including the project as a dependency (e.g. yarn add "wa-sqlite@rhashimoto/wa-sqlite#buildless").

If you do want to build - e.g. you want to change build flags or use a specific EMSDK version - here are the prerequisites:

• Building on Linux is known to work, compatibility with other platforms is unknown.
• yarn - If you use a different package manager (e.g. npm) then file paths in the demo will need adjustment.
• Emscripten SDK - Note that there is a regression in EMSDK 2.0.14 that prevents building.
• curl, make, openssl, sed, unzip

Here are the build steps:

• Make sure emcc works.
• git clone ...
• cd wa-sqlite
• yarn install
• make (or yarn prepack)

The default build produces ES6 modules + WASM, synchronous and asynchronous (using Asyncify) in dist/.

Javascript wrappers for core SQLITE C API functions (and some others) are provided. Some convenience functions are also provided to reduce boilerplate. Here's sample code to load the library and call the API:

  import SQLiteESMFactory from 'wa-sqlite/dist/wa-sqlite.mjs';
  import * as SQLite from 'wa-sqlite';

  async function hello() {
    const module = await SQLiteESMFactory();
    const sqlite3 = SQLite.Factory(module);
    const db = await sqlite3.open_v2('myDB');
    await sqlite3.exec(db, `SELECT 'Hello, world!'`, (row, columns) => {
      console.log(row);
    });
    await sqlite3.close(db);
  }

  hello();

The implementation of sqlite3.exec may be of interest to anyone wanting more fine-grained use of SQLite statement objects (e.g. for binding parameters, explicit column datatypes, etc.).

API reference

To serve the demo directly from the source tree:

• yarn start
• Open a browser on http://localhost:8000/demo/

The demo page provides access to databases on multiple VFS implementations, including IndexedDB (which is the only one persistent across page loads and multiple tabs). In addition, in each database there is a SQLite module named "array" that provides some historical stock data from a common Javascript array - use it for virtual tables in SQL like this:

CREATE VIRTUAL TABLE IF NOT EXISTS goog USING array;

-- Use it directly out of the Javascript array:
SELECT * FROM goog LIMIT 5;

-- Copy into a native table (on the current VFS):
CREATE TABLE IF NOT EXISTS tbl AS SELECT * FROM goog;

For convenience, if any text region is selected in the editor, only that region will be executed. In addition, the editor contents are restored across page reloads using browser localStorage.