feat: Add option for custom banners (#14)

index.js

@@ -76,7 +76,7 @@ module.exports = function(content, ...rest) {
   const { failed, success } = makeDoneHandlers(this.async(), content, rest);
 
   const filename = this.resourcePath;
-  const { mode = 'emit' } = loaderUtils.getOptions(this) || {};
+  const { mode = 'emit', banner = bannerMessage } = loaderUtils.getOptions(this) || {};
   if (!validModes.includes(mode)) {
     return failed(new Error(`Invalid mode option: ${mode}`));
   }
@@ -96,7 +96,7 @@ module.exports = function(content, ...rest) {
     }
   }
 
-  const cssModuleDefinition = `${bannerMessage}\n${cssModuleToInterface(cssModuleKeys)}\n${cssModuleExport}`;
+  const cssModuleDefinition = `${banner}\n${cssModuleToInterface(cssModuleKeys)}\n${cssModuleExport}`;
 
   if (mode === 'verify') {
     read((err, fileContents) => {

test/banner-custom/.gitignore

@@ -0,0 +1 @@
+index.css.d.ts

test/banner-custom/__snapshots__/banner-custom.test.js.snap

@@ -0,0 +1,11 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Can add custom banners 1`] = `
+"// @generated
+interface CssExports {
+  'foo': string;
+}
+export const cssExports: CssExports;
+export default cssExports;
+"
+`;

test/banner-custom/banner-custom.test.js

@@ -0,0 +1,15 @@
+const fs = require('fs');
+const compiler = require('../compiler.js');
+
+test('Can add custom banners', async () => {
+  await compiler(require.resolve('./index.js'), {
+    banner: "// @generated",
+  });
+
+  const declaration = fs.readFileSync(
+    require.resolve('./index.css.d.ts'),
+    'utf-8'
+  );
+
+  expect(declaration).toMatchSnapshot();
+});

test/banner-custom/index.css

@@ -0,0 +1,3 @@
+.foo {
+  display: block;
+}

test/banner-custom/index.js

@@ -0,0 +1 @@
+import styles from './index.css';