Support a config file with a CJS extension and use it preferentially.

lib/configLoaders.js

@@ -1,14 +1,14 @@
 const fs = require("fs");
 const path = require("path");
 
-exports.js = configModule => rootDir => {
-  try {
+exports.js = configModules => rootDir => {
+  for (const configModule of configModules) {
     const file = path.join(rootDir, configModule);
-    const data = require(file);
-
-    return data;
-  } catch (e) {
-    // ignore
+    try {
+      return require(file);
+    } catch (e) {
+      // ignore
+    }
   }
 
   return null;

lib/resolveConfig.js

@@ -6,8 +6,8 @@ const isExt = ext => /^[.][a-z]+/.test(ext);
 const optsToConfigLoaders = opts => {
   const loaders = [];
 
-  if (opts.configModule) {
-    loaders.push(configLoaders.js(opts.configModule));
+  if (opts.configModules) {
+    loaders.push(configLoaders.js(opts.configModules));
   }
 
   if (opts.configFile) {

register.js

@@ -3,7 +3,7 @@ const resolveConfig = require("./lib/resolveConfig");
 const config = resolveConfig({
   cwd: process.cwd(),
   configFile: "package.json",
-  configModule: "mocha-dominate.config.js"
+  configModules: ["mocha-dominate.config.cjs", "mocha-dominate.config.js"]
 });
 
 const hookEach = () => {

test/integration/index.spec.js

@@ -105,20 +105,31 @@ describe("integration", () => {
     });
   });
 
-  it("should work for exampleconfig", () => {
-    const cwd = path.join(TESTDATA, "exampleconfig");
+  describe("with a separate config file", () => {
+    it("should load config options from mocha.config.js", () => {
+      const cwd = path.join(TESTDATA, "exampleconfig");
 
-    return spawnMochaInDir(cwd, ["-r", "../../register"]);
-  });
+      return spawnMochaInDir(cwd, ["-r", "../../register"]);
+    });
 
-  it("should bail on invalid extension", () => {
-    const cwd = path.join(TESTDATA, "exampleconfig-bad");
+    it("should prefer config options from mocha.config.cjs", () => {
+      // if .cjs is not loaded first the test will fail as
+      // the fallback config file is missing the CSS transform
 
-    return expect(
-      () => spawnMochaInDir(cwd, ["-r", "../../register"]),
-      "to be rejected"
-    ).then(err => {
-      expect(err.stderr, "to contain", `invalid extension "less"`);
+      const cwd = path.join(TESTDATA, "exampleconfig-cjs");
+
+      return spawnMochaInDir(cwd, ["-r", "../../register"]);
+    });
+
+    it("should bail on invalid extension", () => {
+      const cwd = path.join(TESTDATA, "exampleconfig-bad");
+
+      return expect(
+        () => spawnMochaInDir(cwd, ["-r", "../../register"]),
+        "to be rejected"
+      ).then(err => {
+        expect(err.stderr, "to contain", `invalid extension "less"`);
+      });
     });
   });
 

testdata/exampleconfig-cjs/example.less

@@ -0,0 +1 @@
+@fontColor: #333;

testdata/exampleconfig-cjs/mocha-dominate.config.cjs

@@ -0,0 +1,5 @@
+module.exports = {
+  transform: {
+    ".less": "<rootDir>/transforms/cssTransform.js"
+  }
+};

testdata/exampleconfig-cjs/mocha-dominate.config.js

@@ -0,0 +1 @@
+module.exports = {};

testdata/exampleconfig-cjs/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "exampleconfig",
+  "version": "0.0.0"
+}

testdata/exampleconfig-cjs/test.js

@@ -0,0 +1,7 @@
+const assert = require("assert");
+
+describe("exampleconfig", () => {
+  it("should ignore less", () => {
+    assert.deepEqual(require("./example.less"), { cssModule: true });
+  });
+});

testdata/exampleconfig-cjs/transforms/cssTransform.js

@@ -0,0 +1,5 @@
+module.exports = {
+  process() {
+    return "module.exports = { cssModule: true };";
+  }
+};