diff --git a/src/utils.js b/src/utils.js
index c593fb1..17a0c6b 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -7,7 +7,7 @@ const camelCase = require("camelcase");
  * @returns {string[]}
  */
 const getCssModuleKeys = content => {
-  const keyRegex = /"([^\\"]+)":/g;
+  const keyRegex = /"([\w-]+)":/g;
   let match;
   const cssModuleKeys = [];
 
diff --git a/test/utils.test.js b/test/utils.test.js
index 90c729e..4ad272c 100644
--- a/test/utils.test.js
+++ b/test/utils.test.js
@@ -1,5 +1,5 @@
 // @ts-check
-const { filenameToPascalCase } = require("../src/utils");
+const { filenameToPascalCase, getCssModuleKeys } = require("../src/utils");
 
 describe("filenameToPascalCase", () => {
   it("camelCase", () => {
@@ -22,3 +22,42 @@ describe("filenameToPascalCase", () => {
     expect(actual).toBe("ReactDatePicker");
   });
 });
+
+describe("getCssModuleKeys", () => {
+  it("empty CSS module", () => {
+    const content = `
+      exports = module.exports = require("../node_modules/css-loader/dist/runtime/api.js")(false);
+      // Module
+      exports.push([module.id, "", ""]);
+    `;
+    const actual = getCssModuleKeys(content);
+    expect(actual).toEqual([]);
+  });
+
+  it("CSS module with one class", () => {
+    const content = `exports.locals = {
+      "test": "test"
+    };`
+    const actual = getCssModuleKeys(content);
+    expect(actual).toEqual(['test']);
+  });
+
+  it("CSS module with multiple classes", () => {
+    const content = `exports.locals = {
+      "test1": "test1",
+      "test2": "test2"
+    };`
+    const actual = getCssModuleKeys(content);
+    expect(actual).toEqual(['test1', 'test2']);
+  });
+
+  it("CSS module with :root pseudo-class only", () => {
+    const content = `
+      exports = module.exports = require("../node_modules/css-loader/dist/runtime/api.js")(false);
+      // Module
+      exports.push([module.id, ":root {\n  --background: green; }\n", ""]);
+    `;
+    const actual = getCssModuleKeys(content);
+    expect(actual).toEqual([]);
+  });
+});