diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index cfec9fc..128aec0 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -19,6 +19,8 @@ jobs:
                   cache: "yarn"
             - name: Install dependencies
               run: yarn install --immutable
+            - name: Check package.json library usage
+              run: yarn packagejson:check
             - name: Spell checking with Cspell
               run: yarn cspell:ci
             - name: Lint codebase with Eslint
diff --git a/lint-staged.config.cjs b/lint-staged.config.cjs
index 4f1bcae..e8615ea 100644
--- a/lint-staged.config.cjs
+++ b/lint-staged.config.cjs
@@ -1,5 +1,5 @@
 module.exports = {
-	"package.json": ['yarn packagejson:format'],
+	"package.json": ['yarn packagejson:format', 'yarn packagejson:check'],
 	"**/*.ts": () => ["tsc -p tsconfig.json --noEmit"],
 	"**/*.{ts,mts,cts,js,mjs,cjs}": (filenames) => `eslint -c .eslintrc.cjs ${filenames.join(" ")} --fix --cache`,
 };
diff --git a/package.json b/package.json
index a9ef013..ef75cde 100644
--- a/package.json
+++ b/package.json
@@ -17,12 +17,12 @@
 		"access": "public",
 		"registry": " https://registry.npmjs.org"
 	},
-	"main": "./lib/cjs/index.cjs",
+	"type": "module",
 	"exports": {
 		".": {
 			"types": "./lib/types/index.d.ts",
 			"require": "./lib/cjs/index.cjs",
-			"default": "./lib/cjs/index.cjs"
+			"import": "./lib/esm/index.js"
 		}
 	},
 	"files": [
@@ -30,8 +30,8 @@
 	],
 	"types": "./lib/types/index.d.ts",
 	"scripts": {
-		"build": "yarn clean && yarn build:cjs",
-		"build:cjs": "tsc -b tsconfig.build.cjs.json",
+		"build": "yarn clean && yarn build:cjs && yarn build:esm",
+		"build:cjs": "tsc -b tsconfig.build.cjs.json && ./scripts/convert-to-cjs.sh",
 		"build:esm": "tsc -b tsconfig.build.esm.json",
 		"clean": "rm -rfv reports coverage build dist lib .eslintcache",
 		"commit": "cz",
@@ -43,6 +43,7 @@
 		"postinstall": "husky install",
 		"prepack": "pinst --disable",
 		"postpack": "pinst --enable",
+		"packagejson:check": "package-check",
 		"packagejson:format": "prettier-package-json --write ./package.json",
 		"test": "yarn test:unit",
 		"test:mutation": "stryker run",
@@ -56,6 +57,7 @@
 		"@commitlint/cli": "^17.0.2",
 		"@commitlint/config-conventional": "^17.0.2",
 		"@commitlint/cz-commitlint": "^17.0.0",
+		"@skypack/package-check": "^0.2.2",
 		"@stryker-mutator/core": "^6.0.2",
 		"@stryker-mutator/mocha-runner": "^6.0.2",
 		"@stryker-mutator/typescript-checker": "^6.0.2",
diff --git a/scripts/convert-to-cjs.sh b/scripts/convert-to-cjs.sh
new file mode 100755
index 0000000..de9bc31
--- /dev/null
+++ b/scripts/convert-to-cjs.sh
@@ -0,0 +1,11 @@
+echo "Converting .js files to .cjs"
+
+FILES=$(find "./lib" -name "*.js")
+
+for path in $FILES
+do
+    echo "Editing $path"
+    sed -r -i "" "s/(require ?[^\"]+\"([^\"]+))\.js/\1.cjs/" "$path"
+    mv "$path" "${path/%.js/.cjs}"
+done
+echo "Done converting files to .cjs"
diff --git a/tsconfig.build.cjs.json b/tsconfig.build.cjs.json
index 4a5eb46..a7f7dcf 100644
--- a/tsconfig.build.cjs.json
+++ b/tsconfig.build.cjs.json
@@ -4,8 +4,8 @@
 		"outDir": "./lib/cjs",
 		"target": "ES2015",
 		"module": "CommonJS",
-		"declarationDir": "./lib/types",
-		"esModuleInterop": true
+		"declaration": false,
+		"declarationMap": false
 	},
 	"include": ["./src/**/*"]
 }
diff --git a/tsconfig.build.json b/tsconfig.build.json
index 7fc6c4c..1e04dcf 100644
--- a/tsconfig.build.json
+++ b/tsconfig.build.json
@@ -3,7 +3,7 @@
 	"compilerOptions": {
 		"baseUrl": ".",
 		"declaration": true,
-		"declarationMap": false,
+		"declarationMap": true,
 		"removeComments": false,
 		"sourceMap": false,
 		"noEmit": false,
diff --git a/yarn.lock b/yarn.lock
index 6c1067c..13d4fd0 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1604,6 +1604,18 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@skypack/package-check@npm:^0.2.2":
+  version: 0.2.2
+  resolution: "@skypack/package-check@npm:0.2.2"
+  dependencies:
+    kleur: ^4.1.3
+    yargs-parser: ^20.2.3
+  bin:
+    package-check: index.bin.js
+  checksum: 7b35c331609b743815ba9d2a7d789e8157d5119ea167fe684cd9d95978892d01aac0e36db5ea8d54fc565e5f57f3732a9793c5c711d454ce9bf1581f34829e9f
+  languageName: node
+  linkType: hard
+
 "@stryker-mutator/api@npm:6.0.2":
   version: 6.0.2
   resolution: "@stryker-mutator/api@npm:6.0.2"
@@ -5453,6 +5465,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"kleur@npm:^4.1.3":
+  version: 4.1.4
+  resolution: "kleur@npm:4.1.4"
+  checksum: 7f6db36e378045dec14acd3cbf0b1e59130c09e984ee8b8ce56dd2d2257cfff90389c1e8f8b19bd09dd5d241080566a814b4ccd99fdcef91f59ef93ec33c8a44
+  languageName: node
+  linkType: hard
+
 "levn@npm:^0.4.1":
   version: 0.4.1
   resolution: "levn@npm:0.4.1"
@@ -8686,6 +8705,7 @@ __metadata:
     "@commitlint/cli": ^17.0.2
     "@commitlint/config-conventional": ^17.0.2
     "@commitlint/cz-commitlint": ^17.0.0
+    "@skypack/package-check": ^0.2.2
     "@stryker-mutator/core": ^6.0.2
     "@stryker-mutator/mocha-runner": ^6.0.2
     "@stryker-mutator/typescript-checker": ^6.0.2