ReWorker

Type-safe message passing for Chrome extensions with automatic chunking. Zero dependencies.

Install

npm install @bluehotdog/reworker

Usage

Define messages with GADTs:

type Types.message<_> +=
  | GetUser(string): Types.message<User.t>
  | SaveData(data): Types.message<Result.t<unit, string>>

Send messages:

module Runtime = Runtime.Make(WxtRuntime)

// Promise-based API
Runtime.sendMessage(GetUser("123"))->Promise.then(user => Console.log(user))

// With async/await
let user = await Runtime.sendMessage(GetUser("123"))
Console.log(user)

// Fire-and-forget
Runtime.cast(SaveData(userData))

Handle messages:

let handler = (msg, _sender) => {
  switch msg {
  | GetUser(id) => Response.now(Database.getUser(id))
  | SaveData(data) => Response.now(Database.save(data))
  | _ => Response.none
  }
}
Runtime.OnMessage.addListener(handler)

Build a nice wrapper: In your background.res:

let getUser = (userid)=> Runtime.sendMessage(GetUser(userid))

This allows callers to just do let user = await Background.getUser("123") Simple. Clear.

Features

• Type safety: GADTs ensure request/response type matching
• Promise-based: Native Manifest V3 promise support with async/await
• Auto-chunking: Handles Chrome's 64MB message limits transparently
• Framework agnostic: Works with any Chrome extension framework
• Zero deps: Pure ReScript library

Requirements

• ReScript ^12.0.0-beta.12
• Manifest V3 extensions only

License

MIT

Thanks

@diogomqbm for foundational work.