fix: Allow Workers to be instantiated directly via callback

packages/core/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@alleninstitute/vis-core",
-    "version": "0.0.5",
+    "version": "0.0.6",
     "contributors": [
         {
             "name": "Lane Sawyer",

packages/core/src/index.ts

@@ -31,4 +31,4 @@ export {
     HEARTBEAT_RATE_MS,
 } from './workers/messages';
 
-export { WorkerPool } from './workers/worker-pool';
+export { WorkerPool, type WorkerInit } from './workers/worker-pool';

packages/core/src/workers/worker-pool.ts

@@ -12,6 +12,10 @@ type MessageValidator<T> = TypeGuardFunction<unknown, T>;
 
 type TypeGuardFunction<T, S extends T> = (value: T) => value is S;
 
+export type WorkerInstantiationCallback = () => Worker;
+
+export type WorkerInit = URL | WorkerInstantiationCallback;
+
 type MessagePromise = {
     validator: MessageValidator<WorkerMessageWithId>;
     resolve: PromiseResolve<WorkerMessageWithId>;
@@ -30,11 +34,15 @@ export class WorkerPool {
     #timeOfPreviousHeartbeat: Map<number, number>;
     #which: number;
 
-    constructor(size: number, workerModule: URL) {
+    constructor(size: number, workerInit: WorkerInit) {
         this.#workers = new Array(size);
         this.#timeOfPreviousHeartbeat = new Map();
         for (let i = 0; i < size; i++) {
-            this.#workers[i] = new Worker(workerModule, { type: 'module' });
+            if (workerInit instanceof URL) {
+                this.#workers[i] = new Worker(workerInit, { type: 'module' });
+            } else {
+                this.#workers[i] = workerInit();
+            }
             this.#workers[i].onmessage = (msg) => this.#handleMessage(i, msg);
             this.#timeOfPreviousHeartbeat.set(i, 0);
         }

packages/omezarr/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@alleninstitute/vis-omezarr",
-    "version": "0.0.15",
+    "version": "0.0.16",
     "contributors": [
         {
             "name": "Lane Sawyer",

packages/omezarr/src/zarr/cache-lower.ts

@@ -2,10 +2,10 @@ import type { OmeZarrShapedDataset, OmeZarrMetadata } from './types';
 import { type ZarrRequest, buildQuery, loadZarrArrayFileFromStore } from './loading';
 import { VisZarrDataError } from '../errors';
 import * as zarr from 'zarrita';
-import { logger } from '@alleninstitute/vis-core';
+import { logger, type WorkerInit } from '@alleninstitute/vis-core';
 import { ZarrFetchStore, type CachingMultithreadedFetchStoreOptions } from './cached-loading/store';
 
-export function decoderFactory(url: string, workerModule: URL, options?: CachingMultithreadedFetchStoreOptions) {
+export function decoderFactory(url: string, workerModule: WorkerInit, options?: CachingMultithreadedFetchStoreOptions) {
     const store = new ZarrFetchStore(url, workerModule, options);
     const getSlice = async (
         metadata: OmeZarrMetadata,

packages/omezarr/src/zarr/cached-loading/store.ts

@@ -1,4 +1,4 @@
-import { type Cacheable, logger, PriorityCache, WorkerPool } from '@alleninstitute/vis-core';
+import { type Cacheable, logger, PriorityCache, type WorkerInit, WorkerPool } from '@alleninstitute/vis-core';
 import * as zarr from 'zarrita';
 import { FETCH_MESSAGE_TYPE, type FetchResponseMessage, isFetchResponseMessage } from './fetch-data.interface';
 
@@ -310,8 +310,9 @@ export class CachingMultithreadedFetchStore extends zarr.FetchStore {
         return this.#doFetch(key, range, workerOptions, abort);
     }
 }
+
 export class ZarrFetchStore extends CachingMultithreadedFetchStore {
-    constructor(url: string | URL, workerModule: URL, options?: CachingMultithreadedFetchStoreOptions) {
+    constructor(url: string | URL, workerModule: WorkerInit, options?: CachingMultithreadedFetchStoreOptions) {
         super(url, new WorkerPool(options?.numWorkers ?? DEFAULT_NUM_WORKERS, workerModule), options);
     }
 }