Fix unable to use node builtins in config file

.changeset/quiet-ways-attend.md

@@ -0,0 +1,5 @@
+---
+'wmr': patch
+---
+
+Fix unable to load node builtins in config file

packages/wmr/src/lib/compile-single-module.js

@@ -20,7 +20,15 @@ const ROLLUP_FAST_OUTPUT = {
 // @TODO: this cache needs to be sharded by `input` in order to actually do anything when `preserveModules:true` is enabled
 let cache;
 
-export const compileSingleModule = withCache(async (input, { cwd, out, hmr = true }) => {
+/**
+ * @param {string} input
+ * @param {object} options
+ * @param {string} options.cwd
+ * @param {string} options.out
+ * @param {boolean} [options.hmr]
+ * @param {boolean} [options.rewriteNodeImports]
+ */
+export const compileSingleModule = withCache(async (input, { cwd, out, hmr = true, rewriteNodeImports = true }) => {
 	input = input.replace(/\.css\.js$/, '.css');
 	// console.log('compiling ' + input);
 	const bundle = await rollup.rollup({
@@ -41,7 +49,7 @@ export const compileSingleModule = withCache(async (input, { cwd, out, hmr = tru
 					// hmr client
 					if (id === 'wmr') id = '/_wmr.js';
 					// bare specifier = npm dep
-					else if (!/^\.?\.?(\/|$)/.test(id)) id = `/@npm/${id}`;
+					else if (rewriteNodeImports && !/^\.?\.?(\/|$)/.test(id)) id = `/@npm/${id}`;
 					// relative imports (css)
 					else if (/\.css$/.test(id)) id += '.js';
 					return { id, external: true, moduleSideEffects: true };

packages/wmr/src/lib/normalize-options.js

@@ -77,7 +77,7 @@ export async function normalizeOptions(options, mode) {
 				// Create a temporary file to write compiled output into
 				// TODO: Do this in memory
 				configFile = resolve(options.root, 'wmr.config.js');
-				await compileSingleModule(file, { cwd: options.cwd, out: resolve('.'), hmr: false });
+				await compileSingleModule(file, { cwd: options.cwd, out: resolve('.'), hmr: false, rewriteNodeImports: false });
 			}
 
 			const fileUrl = url.pathToFileURL(configFile);

packages/wmr/test/fixtures.test.js

@@ -592,6 +592,17 @@ describe('fixtures', () => {
 		});
 	});
 
+	describe('config', () => {
+		it('should support loading node built-ins', async () => {
+			await loadFixture('config-node-builtins', env);
+			instance = await runWmrFast(env.tmp.path);
+
+			await waitForMessage(instance.output, /foo\/bar/);
+			await waitForMessage(instance.output, /plugin-A/);
+			expect(true).toEqual(true); // Silence linter
+		});
+	});
+
 	describe('plugins', () => {
 		it('should order by plugin.enforce value', async () => {
 			await loadFixture('plugin-enforce', env);

packages/wmr/test/fixtures/config-node-builtins/index.html

@@ -0,0 +1 @@
+<h1>Hello world</h1>

packages/wmr/test/fixtures/config-node-builtins/wmr.config.mjs

@@ -0,0 +1,10 @@
+import path from 'path';
+import { pluginA } from './wmr/a.mjs';
+
+export default function wmr() {
+	// Random path usage to check if it works
+	const random = path.join('foo', 'bar').split(path.sep).join(path.posix.sep);
+	return {
+		plugins: [{ name: random }, pluginA()]
+	};
+}

packages/wmr/test/fixtures/config-node-builtins/wmr/a.mjs

@@ -0,0 +1,5 @@
+export function pluginA() {
+	return {
+		name: 'plugin-A'
+	};
+}