fix: enhance setOptions to support both ES modules and CommonJS config exports

#1340

Author: Ffloriel

packages/purgecss/__tests__/cli/cli-config-file.test.ts

@@ -0,0 +1,97 @@
+import { Command } from "commander";
+import * as fs from "fs";
+import * as path from "path";
+import { parseCommandOptions, getOptions } from "../../src/bin";
+import { setOptions } from "../../src";
+
+describe("PurgeCSS CLI config file loading", () => {
+  const testDir = path.join(__dirname, "../test_examples/config-loading");
+  const cjsConfigPath = path.join(testDir, "purgecss.config.cjs");
+  const cssPath = path.join(testDir, "test.css");
+  const htmlPath = path.join(testDir, "test.html");
+
+  beforeAll(() => {
+    // Create test directory and files
+    fs.mkdirSync(testDir, { recursive: true });
+
+    // CommonJS config with module.exports
+    // This tests the fix for: https://github.com/FullHuman/purgecss/issues/XXX
+    // When using `await import()` with CommonJS, Node.js wraps the export in
+    // `{ default: {...} }`, which needs to be properly extracted.
+    fs.writeFileSync(
+      cjsConfigPath,
+      'module.exports = { blocklist: ["blocked"], fontFace: true };',
+    );
+
+    // Test CSS file
+    fs.writeFileSync(
+      cssPath,
+      ".used { color: red; } .blocked { color: blue; }",
+    );
+
+    // Test HTML file
+    fs.writeFileSync(htmlPath, '<div class="used"></div>');
+  });
+
+  afterAll(() => {
+    // Clean up test files
+    fs.rmSync(testDir, { recursive: true, force: true });
+  });
+
+  describe("setOptions", () => {
+    it("should correctly load CommonJS config with module.exports", async () => {
+      const originalCwd = process.cwd();
+      process.chdir(testDir);
+
+      try {
+        const options = await setOptions("purgecss.config.cjs");
+        expect(options.blocklist).toEqual(["blocked"]);
+        expect(options.fontFace).toBe(true);
+      } finally {
+        process.chdir(originalCwd);
+      }
+    });
+  });
+
+  describe("getOptions with config file", () => {
+    it("should load and merge CommonJS config from --config flag", async () => {
+      const program = parseCommandOptions(new Command());
+      program.parse([
+        "purgecss",
+        "",
+        "--css",
+        cssPath,
+        "--content",
+        htmlPath,
+        "--config",
+        cjsConfigPath,
+      ]);
+
+      const options = await getOptions(program);
+      expect(options.blocklist).toEqual(["blocked"]);
+      expect(options.fontFace).toBe(true);
+    });
+
+    it("should allow CLI options to override config file options", async () => {
+      const program = parseCommandOptions(new Command());
+      program.parse([
+        "purgecss",
+        "",
+        "--css",
+        cssPath,
+        "--content",
+        htmlPath,
+        "--config",
+        cjsConfigPath,
+        "--blocklist",
+        "overridden",
+      ]);
+
+      const options = await getOptions(program);
+      // CLI blocklist should override config file blocklist
+      expect(options.blocklist).toEqual(["overridden"]);
+      // Config file fontFace should still be applied
+      expect(options.fontFace).toBe(true);
+    });
+  });
+});

packages/purgecss/src/index.ts

@@ -90,7 +90,12 @@ export async function setOptions(
   let options: Options;
   try {
     const t = path.resolve(process.cwd(), configFile);
-    options = await import(t);
+    const importedConfig = await import(t);
+    // Handle both ES modules (direct export) and CommonJS (default export)
+    options =
+      importedConfig.default && typeof importedConfig.default === "object"
+        ? importedConfig.default
+        : importedConfig;
   } catch (err: unknown) {
     if (err instanceof Error) {
       throw new Error(`${ERROR_CONFIG_FILE_LOADING} ${err.message}`);