fix: resolve Solid server builds for webworker SSR targets

.changeset/ssr-webworker-worker-condition.md

@@ -0,0 +1,5 @@
+---
+'@solidjs/vite-plugin': patch
+---
+
+Server builds with `ssr.target: 'webworker'` now resolve the server builds of `solid-js` and `@solidjs/web`. The plugin adds the `worker` export condition to that environment, so `renderToString` and the other server APIs no longer resolve to their browser stubs (#153).

src/index.ts

@@ -1699,6 +1699,11 @@ export default function solidPlugin(options: Partial<Options> = {}): Plugin[] {
       }
       config.resolve.conditions = [
         'solid',
+        // A server build with `ssr.target: 'webworker'` starts from Vite's
+        // client conditions, which select the browser builds of `solid-js`
+        // and `@solidjs/web`. Their `worker` export points at the server
+        // build, so add it for that environment. #153
+        ...(opts.isSsrTargetWebworker ? ['worker'] : []),
         ...(replaceDev ? ['development'] : []),
         // `development` nests above `observe` in the runtime's exports, so
         // both may be present: dev serve keeps the dev build, builds get the

src/ssr-webworker.test.ts

@@ -0,0 +1,73 @@
+import { mkdtemp, mkdir, rm, writeFile } from 'node:fs/promises';
+import { tmpdir } from 'node:os';
+import path from 'node:path';
+import { build, type Rolldown } from 'vite';
+import { afterAll, beforeAll, describe, expect, it } from 'vitest';
+import solidPlugin from './index.js';
+
+let root: string;
+
+beforeAll(async () => {
+  root = await mkdtemp(path.join(tmpdir(), 'solid-ssr-worker-'));
+  // Mirrors the export map of solid-js: `worker` selects the server build.
+  const solid = path.join(root, 'node_modules/solid-js');
+  await mkdir(solid, { recursive: true });
+  await writeFile(
+    path.join(solid, 'package.json'),
+    JSON.stringify({
+      name: 'solid-js',
+      version: '2.0.0',
+      type: 'module',
+      exports: {
+        '.': {
+          worker: './server.js',
+          browser: './browser.js',
+          node: './server.js',
+          default: './browser.js',
+        },
+      },
+    }),
+  );
+  await writeFile(path.join(solid, 'server.js'), 'export const build = "server";\n');
+  await writeFile(path.join(solid, 'browser.js'), 'export const build = "browser";\n');
+  await writeFile(path.join(root, 'package.json'), JSON.stringify({ name: 'app', type: 'module' }));
+  await writeFile(path.join(root, 'entry.js'), "export { build } from 'solid-js';\n");
+});
+
+afterAll(async () => {
+  await rm(root, { recursive: true, force: true });
+});
+
+async function buildSsr(ssr: Record<string, unknown>) {
+  const result = (await build({
+    root,
+    configFile: false,
+    logLevel: 'silent',
+    plugins: [solidPlugin({ ssr: true })],
+    ssr: { noExternal: true, ...ssr },
+    build: {
+      ssr: path.join(root, 'entry.js'),
+      write: false,
+      minify: false,
+    },
+  })) as Rolldown.RolldownOutput | Rolldown.RolldownOutput[];
+  const output = Array.isArray(result) ? result[0] : result;
+  return output.output
+    .filter((chunk): chunk is Rolldown.OutputChunk => chunk.type === 'chunk')
+    .map((chunk) => chunk.code)
+    .join('\n');
+}
+
+describe('ssr.target webworker', () => {
+  // #153: the webworker SSR build resolved the browser build of solid-js.
+  it('resolves the server build through the worker condition', async () => {
+    const code = await buildSsr({ target: 'webworker' });
+    expect(code).toContain('"server"');
+    expect(code).not.toContain('"browser"');
+  });
+
+  it('still resolves the server build for the node target', async () => {
+    const code = await buildSsr({});
+    expect(code).toContain('"server"');
+  });
+});