jam

Jam is an application server for isolated JavaScript. It runs JavaScript (and TypeScript) per request with isolated execution contexts, inspired by the PHP-FPM model.

Install

``sh
npm install -g jam
jam --help
`

Usage

Create a scripts/app.ts file:

`ts
export default {
fetch(request: Request): Response {
return new Response("Hello from Jam");
}
};
`

Start Jam, pointing it at the scripts folder:

`sh
jam ./scripts
`

Now make a request. Jam maps /app to app.ts.

`sh
curl http://localhost:3000/app
`

Edit the file and make the same request again. The next request runs the updated script immediately, with no rebuilds or restarts.

Documentation

To learn more, see the documentation.

How platform binaries are downloaded

The jam package uses platform-specific optional dependencies. During install, npm picks the matching package for your OS/CPU target:

- jam-darwin-arm64
- jam-darwin-x64
- jam-linux-x64
- jam-linux-arm64

Current support is macOS (darwin) and Linux glibc builds. Linux musl and Windows targets are not published yet.

Environment overrides

- JAM_LIBC=glibc|musl: override Linux libc detection.
- JAM_BINARY_PATH=`: run a specific local binary instead of the optional dependency binary.

Local development

Install dependencies with optional dependencies enabled so the matching platform package is available.