diff --git a/index.js b/index.js
index 103442b..6f318ed 100644
--- a/index.js
+++ b/index.js
@@ -57,17 +57,23 @@ module.exports = function(content, ...rest) {
   const filename = this.resourcePath;
   const { mode = 'emit' } = loaderUtils.getOptions(this) || {};
   if (!validModes.includes(mode)) {
-    return callback(new Error(`Invalid mode option: ${mode}`));
+    return failed(new Error(`Invalid mode option: ${mode}`));
   }
 
   const cssModuleInterfaceFilename = filenameToTypingsFilename(filename);
   const { read, write } = makeFileHandlers(cssModuleInterfaceFilename);
 
-  const keyRegex = /"([^\\"]+)":\s*"(?:[^\\"]+)",?$/gm;
+  const keyRegex = /"([^\\"]+)":/g;
   let match;
   const cssModuleKeys = [];
 
-  while ((match = keyRegex.exec(content))) {
+  const localExports = content.split('exports.locals')[1];
+
+  if (!localExports) {
+    return failed(new Error(`No exported locals found for ${filename}`));
+  }
+
+  while ((match = keyRegex.exec(localExports))) {
     if (cssModuleKeys.indexOf(match[1]) < 0) {
       cssModuleKeys.push(match[1]);
     }
diff --git a/package.json b/package.json
index 34ac319..60d908b 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
     "css-loader": "^1.0.0",
     "cz-conventional-changelog": "^2.1.0",
     "husky": "^1.1.2",
-    "jest": "^23.6.0",
+    "jest": "^24.7.1",
     "memory-fs": "^0.4.1",
     "semantic-release": "^15.9.17",
     "travis-deploy-once": "^5.0.9",
diff --git a/test/emit-declaration/__snapshots__/emit-declaration.test.js.snap b/test/emit-declaration/__snapshots__/emit-declaration.test.js.snap
index 8df0751..e58bc9e 100644
--- a/test/emit-declaration/__snapshots__/emit-declaration.test.js.snap
+++ b/test/emit-declaration/__snapshots__/emit-declaration.test.js.snap
@@ -1,9 +1,24 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`Can emit valid declaration with sourceMap 1`] = `
+"// This file is automatically generated.
+// Please do not change this file!
+interface CssExports {
+  'composedClass': string;
+  'otherClass': string;
+  'someClass': string;
+  'validClass': string;
+}
+declare var cssExports: CssExports;
+export = cssExports;
+"
+`;
+
 exports[`Can emit valid declaration without sourceMaps 1`] = `
 "// This file is automatically generated.
 // Please do not change this file!
 interface CssExports {
+  'composedClass': string;
   'otherClass': string;
   'someClass': string;
   'validClass': string;
diff --git a/test/emit-declaration/common.css b/test/emit-declaration/common.css
new file mode 100644
index 0000000..f3c306b
--- /dev/null
+++ b/test/emit-declaration/common.css
@@ -0,0 +1,3 @@
+.baseClass {
+  position: relative;
+}
diff --git a/test/emit-declaration/emit-declaration.test.js b/test/emit-declaration/emit-declaration.test.js
index 8bb7543..7006a94 100644
--- a/test/emit-declaration/emit-declaration.test.js
+++ b/test/emit-declaration/emit-declaration.test.js
@@ -20,17 +20,6 @@ test('Can emit valid declaration with sourceMap', async () => {
     'utf-8'
   );
 
-  expect(declaration).toMatchInlineSnapshot(`
-"// This file is automatically generated.
-// Please do not change this file!
-interface CssExports {
-  'otherClass': string;
-  'someClass': string;
-  'validClass': string;
-}
-declare var cssExports: CssExports;
-export = cssExports;
-"
-`);
+  expect(declaration).toMatchSnapshot();
 });
 
diff --git a/test/emit-declaration/index.css b/test/emit-declaration/index.css
index 8bdba1f..352d143 100644
--- a/test/emit-declaration/index.css
+++ b/test/emit-declaration/index.css
@@ -9,3 +9,8 @@
 .otherClass {
   display: block;
 }
+
+.composedClass {
+  composes: baseClass from './common.css';
+  color: cornflowerblue;
+}