feat(rstream): update defWorker() arg types

- add `WorkerSource` type alias
- add support for zero-arg fns returning a worker instance
  - helps v. much with Vite's `xxx?worker` imports
  - see /examples/mandelbrot for usage

packages/rstream/src/api.ts

@@ -232,3 +232,5 @@ export interface IStream<T> extends ISubscriber<T> {
 
 export type StreamCancel = () => void;
 export type StreamSource<T> = (sub: Stream<T>) => StreamCancel | void;
+
+export type WorkerSource = Worker | Blob | Fn0<Worker> | string;

packages/rstream/src/defworker.ts

@@ -1,9 +1,14 @@
+import { isFunction } from "@thi.ng/checks/is-function";
+import type { WorkerSource } from "./api.js";
+
 export const defInlineWorker = (src: string) =>
     defWorker(new Blob([src], { type: "text/javascript" }));
 
-export const defWorker = (worker: Worker | string | Blob) =>
+export const defWorker = (worker: WorkerSource) =>
     worker instanceof Worker
         ? worker
+        : isFunction(worker)
+        ? worker()
         : new Worker(
               worker instanceof Blob ? URL.createObjectURL(worker) : worker
           );

packages/rstream/src/forkjoin.ts

@@ -5,7 +5,12 @@ import { map } from "@thi.ng/transducers/map";
 import { mapcat } from "@thi.ng/transducers/mapcat";
 import { range } from "@thi.ng/transducers/range";
 import { transduce } from "@thi.ng/transducers/transduce";
-import type { CommonOpts, ISubscribable, ITransformable } from "./api.js";
+import type {
+    CommonOpts,
+    ISubscribable,
+    ITransformable,
+    WorkerSource,
+} from "./api.js";
 import type { Subscription } from "./subscription.js";
 import { sync } from "./sync.js";
 import { tunnel } from "./tunnel.js";
@@ -47,7 +52,7 @@ export interface ForkJoinOpts<IN, MSG, RES, OUT> extends Partial<CommonOpts> {
      * string. In the latter two cases, a worker is created
      * automatically using `makeWorker()`.
      */
-    worker: string | Worker | Blob;
+    worker: WorkerSource;
     /**
      * Optional max number of workers to use. Defaults to
      * `navigator.hardwareConcurrency` (or if unavailable, then 4 as

packages/rstream/src/tunnel.ts

@@ -1,4 +1,4 @@
-import type { Fn } from "@thi.ng/api";
+import type { Fn, Fn0 } from "@thi.ng/api";
 import { State } from "./api.js";
 import { __nextID } from "./idgen.js";
 import { LOGGER } from "./logger.js";
@@ -10,7 +10,7 @@ export interface TunnelOpts<A> {
      * Tunnelled worker instance, source blob or script URL.
      * If `interrupt` is enabled, the worker MUST be given as blob or URL.
      */
-    src: Worker | Blob | string;
+    src: Worker | Blob | string | Fn0<Worker>;
     /**
      * Max. number of worker instances to use. Only useful if
      * `interrupt` is disabled. If more than one worker is used,
@@ -69,7 +69,7 @@ export const tunnel = <A, B>(opts: TunnelOpts<A>) => new Tunnel<A, B>(opts);
  */
 export class Tunnel<A, B> extends Subscription<A, B> {
     workers: Worker[];
-    src: Worker | Blob | string;
+    src: Worker | Blob | string | Fn0<Worker>;
     transferables?: Fn<A, any[]>;
     terminate: number;
     interrupt: boolean;

packages/rstream/src/worker.ts

@@ -1,4 +1,4 @@
-import type { WithErrorHandlerOpts } from "./api.js";
+import type { WithErrorHandlerOpts, WorkerSource } from "./api.js";
 import { defWorker } from "./defworker.js";
 import { __optsWithID } from "./idgen.js";
 import { LOGGER } from "./logger.js";
@@ -38,7 +38,7 @@ export interface FromWorkerOpts extends WithErrorHandlerOpts {
  * @param opts -
  */
 export const fromWorker = <T>(
-    worker: Worker | Blob | string,
+    worker: WorkerSource,
     opts?: Partial<FromWorkerOpts>
 ) => {
     const _worker = defWorker(worker);