fix: load the pdf.js worker with the Map upsert polyfill

src/tests/map-upsert-polyfill.test.ts

@@ -1,4 +1,5 @@
 import { readFileSync } from 'node:fs';
+import { join } from 'node:path';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 
 type MapWithUpsert<K, V> = Map<K, V> & {
@@ -107,7 +108,7 @@ describe('Map upsert polyfill', () => {
 
   it('loads before PDF.js so render can use the methods', () => {
     const mainSource = readFileSync(
-      new URL('../js/main.ts', import.meta.url),
+      join(process.cwd(), 'src/js/main.ts'),
       'utf8'
     );
     const polyfillImport = "import './utils/map-upsert-polyfill.js';";

src/tests/pdf-worker-polyfill.test.ts

@@ -0,0 +1,61 @@
+import { readFileSync, readdirSync, statSync } from 'node:fs';
+import { join } from 'node:path';
+import { describe, expect, it } from 'vitest';
+
+const SRC_JS = join(process.cwd(), 'src/js');
+
+function collectTsFiles(dir: string): string[] {
+  const out: string[] = [];
+  for (const entry of readdirSync(dir)) {
+    const full = join(dir, entry);
+    if (statSync(full).isDirectory()) {
+      out.push(...collectTsFiles(full));
+    } else if (full.endsWith('.ts')) {
+      out.push(full);
+    }
+  }
+  return out;
+}
+
+describe('pdf.js worker polyfill wiring', () => {
+  it('installs the polyfill before loading the pdf.js worker', () => {
+    const entry = readFileSync(join(SRC_JS, 'pdf.worker.ts'), 'utf8');
+    const polyfillAt = entry.indexOf('map-upsert-polyfill');
+    const workerAt = entry.indexOf('pdfjs-dist/build/pdf.worker');
+
+    expect(polyfillAt).toBeGreaterThanOrEqual(0);
+    expect(workerAt).toBeGreaterThanOrEqual(0);
+    expect(polyfillAt).toBeLessThan(workerAt);
+  });
+
+  it('points workerSrc at the wrapped worker', () => {
+    const setup = readFileSync(
+      join(SRC_JS, 'utils/setup-pdf-worker.ts'),
+      'utf8'
+    );
+
+    expect(setup).toContain("from '../pdf.worker?worker&url'");
+    expect(setup).toMatch(/GlobalWorkerOptions\.workerSrc\s*=\s*pdfWorkerUrl/);
+  });
+
+  it('never points workerSrc straight at the unpolyfilled pdf.js worker', () => {
+    const offenders = collectTsFiles(SRC_JS)
+      .filter((f) => !f.endsWith('pdf.worker.ts'))
+      .filter((file) => {
+        const source = readFileSync(file, 'utf8');
+        return /GlobalWorkerOptions\.workerSrc\s*=[\s\S]{0,120}pdfjs-dist\/build\/pdf\.worker/.test(
+          source
+        );
+      });
+
+    expect(offenders).toEqual([]);
+  });
+
+  it('keeps every page that configures pdf.js on the shared setup', () => {
+    const importers = collectTsFiles(SRC_JS).filter((file) =>
+      readFileSync(file, 'utf8').includes('setup-pdf-worker')
+    );
+
+    expect(importers.length).toBeGreaterThan(30);
+  });
+});