diff --git a/src/index.js b/src/index.js
index 13dfedeb..d3a25cfb 100644
--- a/src/index.js
+++ b/src/index.js
@@ -10,7 +10,7 @@ import schema from './options.json';
 const loaderApi = () => {};
 
 loaderApi.pitch = function loader(request) {
-  const options = loaderUtils.getOptions(this);
+  const options = { ...loaderUtils.getOptions(this) };
 
   validateOptions(schema, options, {
     name: 'Style Loader',
diff --git a/test/esModule-option.test.js b/test/esModule-option.test.js
index 2e9e7c6f..75cbb5a1 100644
--- a/test/esModule-option.test.js
+++ b/test/esModule-option.test.js
@@ -17,8 +17,16 @@ describe('"esModule" option', () => {
     'lazySingletonStyleTag',
     'linkTag',
   ];
+  const commonjsExports = {
+    styleTag: 'module.exports = content.locals || {}',
+    singletonStyleTag: 'module.exports = content.locals || {}',
+    lazyStyleTag: 'module.exports = exported',
+    lazySingletonStyleTag: 'module.exports = exported',
+  };
 
   injectTypes.forEach((injectType) => {
+    const commonjsExport = commonjsExports[injectType];
+
     it(`should work when not specified and when the "injectType" option is "${injectType}"`, async () => {
       const entry = getEntryByInjectType('simple.js', injectType);
       const compiler = getCompiler(entry, { injectType });
@@ -37,8 +45,12 @@ describe('"esModule" option', () => {
       const compiler = getCompiler(entry, { injectType, esModule: true });
       const stats = await compile(compiler);
 
-      runInJsDom('main.bundle.js', compiler, stats, (dom) => {
+      runInJsDom('main.bundle.js', compiler, stats, (dom, bundle) => {
         expect(dom.serialize()).toMatchSnapshot('DOM');
+
+        if (commonjsExport) {
+          expect(bundle).not.toEqual(expect.stringContaining(commonjsExport));
+        }
       });
 
       expect(getWarnings(stats)).toMatchSnapshot('warnings');
@@ -74,8 +86,12 @@ describe('"esModule" option', () => {
       );
       const stats = await compile(compiler);
 
-      runInJsDom('main.bundle.js', compiler, stats, (dom) => {
+      runInJsDom('main.bundle.js', compiler, stats, (dom, bundle) => {
         expect(dom.serialize()).toMatchSnapshot('DOM');
+
+        if (commonjsExport) {
+          expect(bundle).not.toEqual(expect.stringContaining(commonjsExport));
+        }
       });
 
       expect(getWarnings(stats)).toMatchSnapshot('warnings');
@@ -117,8 +133,12 @@ describe('"esModule" option', () => {
       );
       const stats = await compile(compiler);
 
-      runInJsDom('main.bundle.js', compiler, stats, (dom) => {
+      runInJsDom('main.bundle.js', compiler, stats, (dom, bundle) => {
         expect(dom.serialize()).toMatchSnapshot('DOM');
+
+        if (commonjsExport) {
+          expect(bundle).not.toEqual(expect.stringContaining(commonjsExport));
+        }
       });
 
       expect(getWarnings(stats)).toMatchSnapshot('warnings');
@@ -130,8 +150,12 @@ describe('"esModule" option', () => {
       const compiler = getCompiler(entry, { injectType, esModule: false });
       const stats = await compile(compiler);
 
-      runInJsDom('main.bundle.js', compiler, stats, (dom) => {
+      runInJsDom('main.bundle.js', compiler, stats, (dom, bundle) => {
         expect(dom.serialize()).toMatchSnapshot('DOM');
+
+        if (commonjsExport) {
+          expect(bundle).toEqual(expect.stringContaining(commonjsExport));
+        }
       });
 
       expect(getWarnings(stats)).toMatchSnapshot('warnings');
@@ -167,8 +191,12 @@ describe('"esModule" option', () => {
       );
       const stats = await compile(compiler);
 
-      runInJsDom('main.bundle.js', compiler, stats, (dom) => {
+      runInJsDom('main.bundle.js', compiler, stats, (dom, bundle) => {
         expect(dom.serialize()).toMatchSnapshot('DOM');
+
+        if (commonjsExport) {
+          expect(bundle).toEqual(expect.stringContaining(commonjsExport));
+        }
       });
 
       expect(getWarnings(stats)).toMatchSnapshot('warnings');
@@ -210,8 +238,12 @@ describe('"esModule" option', () => {
       );
       const stats = await compile(compiler);
 
-      runInJsDom('main.bundle.js', compiler, stats, (dom) => {
+      runInJsDom('main.bundle.js', compiler, stats, (dom, bundle) => {
         expect(dom.serialize()).toMatchSnapshot('DOM');
+
+        if (commonjsExport) {
+          expect(bundle).toEqual(expect.stringContaining(commonjsExport));
+        }
       });
 
       expect(getWarnings(stats)).toMatchSnapshot('warnings');
diff --git a/test/fixtures/simple.js b/test/fixtures/simple.js
index 9784c57c..490afd69 100644
--- a/test/fixtures/simple.js
+++ b/test/fixtures/simple.js
@@ -1,2 +1,2 @@
-import './style.css';
-import './style-other.css';
+import a from './style.css';
+import b from './style-other.css';
diff --git a/test/helpers/runInJsDom.js b/test/helpers/runInJsDom.js
index 088751fb..343a06cc 100644
--- a/test/helpers/runInJsDom.js
+++ b/test/helpers/runInJsDom.js
@@ -32,7 +32,7 @@ function runInJsDom(assetName, compiler, stats, testFn) {
 
     dom.window.eval(bundle);
 
-    testFn(dom);
+    testFn(dom, bundle);
 
     // free memory associated with the window
     dom.window.close();