Make the backend a required argument in createWorker

docs/usage.md

@@ -169,8 +169,7 @@ Bundle this module and you will obtain a stand-alone bundle that has its worker
 ### createWorker - select worker backend
 `createWorker` allows selecting the worker backend (among web, node, and tiny), and also if you want a blob worker.
 
-The second argument to the `createWorker` is an object that specifies `backend: 'web' | 'node' | 'tiny'` and `blob: boolean`.
-You can also pass other `WorkerOptions` in this object.
+The second required argument to the `createWorker` is a string that specifies `backend: 'web' | 'node' | 'tiny'`. The third optional argument is an object that can be used to specify `blob: boolean` or other `WorkerOptions`.
 
 `createWorker` uses dynamic imports to only import the needed implementation, so you can import the needed functions directly to reduce the bundle size.
 
@@ -179,7 +178,7 @@ import { createWorker } from "threads/createWorker"
 import { spawn, Thread } from "threads"
 
 async function run() {
-  const worker = await createWorker("./worker.js", {backend: "node"})
+  const worker = await createWorker("./worker.js", "node")
   const add = await spawn(worker)
   const result = await add(2, 3)
   await Thread.terminate(add)

src/createWorker.ts

@@ -4,20 +4,25 @@ import {
   WorkerImplementation,
 } from "./types/master"
 
-/** async function to creat a webworker. This function uses dynamic imports to only import the required implementation */
-export async function createWorker(workerPath: string & Blob, options: CreateWorkerOptions) {
+/**
+ * async function to creat a webworker. This function uses dynamic imports to only import the required implementation
+ * @param workerPath the path or Blob to the worker code
+ * @param backend backend for the threads
+ * @param {CreateWorkerOptions} options an object that can be used to specify `blob: boolean` or other {WorkerOptions}. Defaults to `{}`.
+ */
+export async function createWorker(workerPath: string & Blob, backend: "web" | "node" | "tiny", options: CreateWorkerOptions = {}) {
   let WorkerConstructor: typeof WorkerImplementation | typeof BlobWorker
-  if (options.backend === "web") {
+  if (backend === "web") {
     const { getWorkerImplementation } = await import("./master/implementation.browser")
     WorkerConstructor = options.blob ?
       getWorkerImplementation().blob :
       getWorkerImplementation().default
-  } else if (options.backend === "node") {
+  } else if (backend === "node") {
     const { getWorkerImplementation } = await import("./master/implementation-node")
     WorkerConstructor = options.blob ?
       getWorkerImplementation("node").blob :
       getWorkerImplementation("node").default
-  } else if (options.backend === "tiny") {
+  } else if (backend === "tiny") {
     const { getWorkerImplementation } = await import("./master/implementation-node")
     WorkerConstructor = options.blob ?
       getWorkerImplementation("tiny").blob :

src/types/master.ts

@@ -89,10 +89,8 @@ export interface ThreadsWorkerOptions extends WorkerOptions {
 }
 
 export interface CreateWorkerOptions extends ThreadsWorkerOptions {
-  /** backend for the threads */
-  backend: "web" | "node" | "tiny"
   /** flag to return a BlobWorker */
-  blob: boolean
+  blob?: boolean
 }
 
 /** Worker implementation. Either web worker or a node.js Worker class. */

test/rollup/app-createWorker.js

@@ -2,7 +2,7 @@ import { createWorker } from "../../createWorker.mjs"
 import { spawn, Thread } from "../../"
 
 async function run() {
-  const add = await spawn(await createWorker("./worker.js", {backend: "node"}))
+  const add = await spawn(await createWorker("./worker.js", "node"))
   const result = await add(2, 3)
   await Thread.terminate(add)
   return result