diff --git a/jsconfig.json b/jsconfig.json
new file mode 100644
index 0000000..aee6398
--- /dev/null
+++ b/jsconfig.json
@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "target": "ESNext",
+    "module": "ESNext",
+    "moduleResolution": "NodeNext",
+    "allowJs": true,
+    "checkJs": true,
+    "resolveJsonModule": true,
+    "noEmit": true
+  }
+}
\ No newline at end of file
diff --git a/src/index.js b/src/index.js
index d67b5f4..71b536c 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,9 +1,8 @@
-import path from 'path';
 import { getInput, setFailed, startGroup, endGroup, debug } from '@actions/core';
 import { context, getOctokit } from '@actions/github';
 import { exec } from '@actions/exec';
 import SizePlugin from 'size-plugin-core';
-import { fileExists, diffTable, toBool, stripHash } from './utils.js';
+import { getPackageManagerAndInstallScript, diffTable, toBool, stripHash } from './utils.js';
 
 /**
  * @typedef {ReturnType<typeof import("@actions/github").getOctokit>} Octokit
@@ -50,27 +49,7 @@ async function run(octokit, context, token) {
 	const buildScript = getInput('build-script') || 'build';
 	const cwd = process.cwd();
 
-	let yarnLock = await fileExists(path.resolve(cwd, 'yarn.lock'));
-	let pnpmLock = await fileExists(path.resolve(cwd, 'pnpm-lock.yaml'));
-	let bunLockb = await fileExists(path.resolve(cwd, 'bun.lockb'));
-	let bunLock = await fileExists(path.resolve(cwd, 'bun.lock'));
-	let packageLock = await fileExists(path.resolve(cwd, 'package-lock.json'));
-
-	let packageManager = 'npm';
-	let installScript = 'npm install';
-	if (yarnLock) {
-		installScript = 'yarn --frozen-lockfile';
-		packageManager = 'yarn';
-	} else if (pnpmLock) {
-		installScript = 'pnpm install --frozen-lockfile';
-		packageManager = 'pnpm';
-	} else if (bunLockb || bunLock) {
-		installScript = 'bun install --frozen-lockfile';
-		packageManager = 'bun';
-	} else if (packageLock) {
-		installScript = 'npm ci';
-	}
-
+	let { packageManager, installScript } = await getPackageManagerAndInstallScript(cwd);
 	if (getInput('install-script')) {
 		installScript = getInput('install-script');
 	}
@@ -128,27 +107,7 @@ async function run(octokit, context, token) {
 
 	startGroup(`[base] Install Dependencies`);
 
-	yarnLock = await fileExists(path.resolve(cwd, 'yarn.lock'));
-	pnpmLock = await fileExists(path.resolve(cwd, 'pnpm-lock.yaml'));
-	bunLockb = await fileExists(path.resolve(cwd, 'bun.lockb'));
-	bunLock = await fileExists(path.resolve(cwd, 'bun.lock'));
-	packageLock = await fileExists(path.resolve(cwd, 'package-lock.json'));
-
-	packageManager = 'npm';
-	installScript = 'npm install';
-	if (yarnLock) {
-		installScript = `yarn --frozen-lockfile`;
-		packageManager = `yarn`;
-	} else if (pnpmLock) {
-		installScript = `pnpm install --frozen-lockfile`;
-		packageManager = `pnpm`;
-	} else if (bunLockb || bunLock) {
-		installScript = `bun install --frozen-lockfile`;
-		packageManager = `bun`;
-	} else if (packageLock) {
-		installScript = `npm ci`;
-	}
-
+	({ packageManager, installScript } = await getPackageManagerAndInstallScript(cwd));
 	if (getInput('install-script')) {
 		installScript = getInput('install-script');
 	}
diff --git a/src/utils.js b/src/utils.js
index 540cd8b..da71df4 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -1,6 +1,38 @@
 import fs from 'fs';
+import path from 'path';
 import prettyBytes from 'pretty-bytes';
 
+/**
+ * @param {string} cwd
+ * @returns {Promise<{ packageManager: string, installScript: string }>}
+ */
+export async function getPackageManagerAndInstallScript(cwd) {
+	const [yarnLockExists, pnpmLockExists, bunLockBinaryExists, bunLockExists, packageLockExists] = await Promise.all([
+		fileExists(path.resolve(cwd, 'yarn.lock')),
+		fileExists(path.resolve(cwd, 'pnpm-lock.yaml')),
+		fileExists(path.resolve(cwd, 'bun.lockb')),
+		fileExists(path.resolve(cwd, 'bun.lock')),
+		fileExists(path.resolve(cwd, 'package-lock.json')),
+	]);
+
+	let packageManager = 'npm';
+	let installScript = 'npm install';
+	if (yarnLockExists) {
+		installScript = 'yarn --frozen-lockfile';
+		packageManager = 'yarn';
+	} else if (pnpmLockExists) {
+		installScript = 'pnpm install --frozen-lockfile';
+		packageManager = 'pnpm';
+	} else if (bunLockBinaryExists || bunLockExists) {
+		installScript = 'bun install --frozen-lockfile';
+		packageManager = 'bun';
+	} else if (packageLockExists) {
+		installScript = 'npm ci';
+	}
+
+	return { packageManager, installScript };
+}
+
 /**
  * Check if a given file exists and can be accessed.
  * @param {string} filename
diff --git a/tests/utils.spec.js b/tests/utils.spec.js
index 5aaef4b..6a39cb8 100644
--- a/tests/utils.spec.js
+++ b/tests/utils.spec.js
@@ -1,4 +1,5 @@
-import { toBool, getDeltaText, iconForDifference, diffTable, fileExists, stripHash } from '../src/utils.js';
+import path from 'path';
+import { toBool, getDeltaText, iconForDifference, diffTable, getPackageManagerAndInstallScript, fileExists, stripHash } from '../src/utils.js';
 
 test('toBool', () => {
 	expect(toBool('1')).toBe(true);
@@ -65,6 +66,18 @@ test('diffTable', () => {
 	expect(diffTable([files[2]], { ...defaultOptions })).toMatchSnapshot();
 });
 
+test('getPackageManagerAndInstallScript', async () => {
+	let cwd = process.cwd();
+	let { packageManager, installScript } = await getPackageManagerAndInstallScript(cwd);
+	expect(packageManager).toBe('npm');
+	expect(installScript).toBe('npm ci');
+
+	cwd = path.join(cwd, 'tests');
+	({ packageManager, installScript } = await getPackageManagerAndInstallScript(cwd));
+	expect(packageManager).toBe('npm');
+	expect(installScript).toBe('npm install');
+});
+
 test('fileExists', async () => {
 	expect(await fileExists('package.json')).toBe(true);
 	expect(await fileExists('file-that-does-not-exist')).toBe(false);