#Install

$ npm install --save offroad

#Setup

1. Add some "paths" entries to your tsconfig.json file:

   // tsconfig.json
   {
     "compilerOptions": {
       // ...
       "paths": {
         "worker:*.ts": ["./src/*.d.ts"],
         "worker:*": ["./src/*.d", "./src/*.d.ts"]
       }
     }
   }

2. Attach the Vite plugin:

   // vite.config.ts
   import { defineConfig } from "vite";
   import { offroad } from "offroad/vite";
   
   export default defineConfig({
     plugins: [
       offroad(),
     ],
   });

3. Use define to define a potential bridge:

   // example.ts
   import { define } from "offroad";
   
   // IMPORTANT: Must be `default` export!
   export default define({
     add(a: number, b: number): number {
       return a + b;
     },
   });

#Usage

Now, anywhere in your Vite application, you may use the example.ts file as per normal:

import example from "./example.ts";

let value = example.add(1, 2); //-> 3

However, you may also import the example.ts as a bridge to a Worker. This is done by adding the worker: prefix to your import statement.

Doing so allows you to interface with the file exactly the same, except now all methods are Promises!

import example from "worker:./example.ts";

let value = await example.add(1, 2); //-> 3

If are unsure if you want a Worker or not, or if you have dynamic/runtime conditions that determine your ability to use a Worker, you may use the offroad helper to conditionally load a module as a Bridge to a Worker or load the module directly:

import { offroad } from "offroad";

// Your custom logic
declare const useWorker: () => boolean;

const example = await offroad(useWorker, {
  worker: () => import("worker:./example"),
  fallback: () => import("./example"),
});

// Option 1:
// Always `await`
let foo = await example.add(2, 3); //-> 5

// Option 2:
// Use `isBridge` to determine if is Bridge (async) or not
import { isBridge } from "offroad";

if (isBridge(example)) {
  // Bridge <-> Worker
  await example.add(2, 3); //-> 5
} else {
  // Direct / Main thread
  example.add(2, 3); //-> 5
}

#License

MIT © Luke Edwards