diff --git a/dist/index.js b/dist/index.js
index 9192615..514e20a 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -14,6 +14,7 @@ var Stream = require('stream');
 var Url = require('url');
 var zlib = require('zlib');
 var childProcess = require('child_process');
+var crypto = require('crypto');
 
 function _interopDefaultLegacy (e) { return e && typeof e === 'object' && 'default' in e ? e : { 'default': e }; }
 
@@ -30,6 +31,7 @@ var Stream__default = /*#__PURE__*/_interopDefaultLegacy(Stream);
 var Url__default = /*#__PURE__*/_interopDefaultLegacy(Url);
 var zlib__default = /*#__PURE__*/_interopDefaultLegacy(zlib);
 var childProcess__default = /*#__PURE__*/_interopDefaultLegacy(childProcess);
+var crypto__default = /*#__PURE__*/_interopDefaultLegacy(crypto);
 
 var commonjsGlobal = typeof globalThis !== 'undefined' ? globalThis : typeof window !== 'undefined' ? window : typeof global !== 'undefined' ? global : typeof self !== 'undefined' ? self : {};
 
@@ -6308,7 +6310,7 @@ var dist = createCommonjsModule(function (module, exports) {
  */
 
 var res = '';
-var cache;
+var cache$1;
 
 /**
  * Expose `repeat`
@@ -6344,8 +6346,8 @@ function repeat(str, num) {
   if (num === 2) return str + str;
 
   var max = str.length * num;
-  if (cache !== str || typeof cache === 'undefined') {
-    cache = str;
+  if (cache$1 !== str || typeof cache$1 === 'undefined') {
+    cache$1 = str;
     res = '';
   } else if (res.length >= max) {
     return res.substr(0, max);
@@ -10819,6 +10821,7 @@ async function upsertComment({
 	core.endGroup();
 }
 
+console.log('dirname', __dirname);
 // import {createTempDirectory} from '@actions/cache/lib/internal/cacheUtils';
 
 const COMMENT_SIGNATURE = sub('🤖 This report was automatically generated by [pkg-size-action](https://github.com/privatenumber/pkg-size-action/)');
@@ -10839,33 +10842,75 @@ async function isBaseDiffFromHead(baseRef) {
 	return exitCode !== 0;
 }
 
+const lockFiles = {
+	'package-lock.json': 'npm ci',
+	'yarn.lock': 'yarn install --frozen-lockfile', // yarn is installed on GitHub Actions by default
+	'pnpm-lock.yaml': 'npx pnpm i --frozen-lockfile', // pnpm is not installed on GitHub Actions by default
+};
+
+function findLockFile(directory) {
+	for (const lockFile in lockFiles) { // eslint-disable-line guard-for-in
+		const lockFilePath = path__default['default'].join(directory, lockFile);
+		if (fs__default['default'].existsSync(lockFilePath)) {
+			return {
+				lockFilePath,
+				command: lockFiles[lockFile],
+			};
+		}
+	}
+
+	return {
+		lockFilePath: undefined,
+		command: 'npm i',
+	};
+}
+
+const getHash = filePath => new Promise(resolve => {
+	const hash = crypto__default['default'].createHash('md5');
+	fs__default['default'].createReadStream(filePath)
+		.on('data', data => hash.update(data))
+		.on('end', () => resolve(hash.digest('hex')));
+});
+
 async function npmCi({cwd} = {}) {
 	if (fs__default['default'].existsSync('node_modules')) {
 		core.info('Cleaning node_modules');
 		await rmRF_1(path__default['default'].join(cwd, 'node_modules'));
 	}
 
-	if (fs__default['default'].existsSync('package-lock.json')) {
-		core.info('Installing dependencies with npm');
-		return await exec$2('npm ci', {cwd});
-	}
+	const packageManager = findLockFile(cwd);
 
-	if (fs__default['default'].existsSync('yarn.lock')) {
-		core.info('Installing dependencies with yarn');
+	console.log(JSON.stringify(packageManager, null, 4));
 
-		// yarn is installed on GitHub Actions by default
-		return await exec$2('yarn install --frozen-lockfile', {cwd});
-	}
+	const packageLockHash = await getHash(packageManager.lockFilePath);
 
-	if (fs__default['default'].existsSync('pnpm-lock.yaml')) {
-		core.info('Installing dependencies with pnpm');
+	const cached = await cache.saveCache(['node_modules'], packageLockHash);
+	console.log('cached', JSON.stringify(cached, null, 4));
 
-		// pnpm is not installed on GitHub Actions by default
-		return await exec$2('npx pnpm i --frozen-lockfile', {cwd});
-	}
+	core.info(`Installing dependencies with ${packageManager.command}`);
+	return await exec$2(packageManager.command, {cwd});
+
+	// if (fs.existsSync('package-lock.json')) {
+	// 	core.info('Installing dependencies with npm');
+	// 	return await exec('npm ci', {cwd});
+	// }
+
+	// if (fs.existsSync('yarn.lock')) {
+	// 	core.info('Installing dependencies with yarn');
+
+	// 	// yarn is installed on GitHub Actions by default
+	// 	return await exec('yarn install --frozen-lockfile', {cwd});
+	// }
+
+	// if (fs.existsSync('pnpm-lock.yaml')) {
+	// 	core.info('Installing dependencies with pnpm');
+
+	// 	// pnpm is not installed on GitHub Actions by default
+	// 	return await exec('npx pnpm i --frozen-lockfile', {cwd});
+	// }
 
-	core.info('No lock file detected. Installing dependencies with npm');
-	return await exec$2('npm i', {cwd});
+	// core.info('No lock file detected. Installing dependencies with npm');
+	// return await exec('npm i', {cwd});
 }
 
 async function isFileTracked(filePath) {
diff --git a/package.json b/package.json
index b88d65a..d57ad1a 100644
--- a/package.json
+++ b/package.json
@@ -38,12 +38,13 @@
 		]
 	},
 	"devDependencies": {
-		"@actions/cache": "^1.0.4",
+		"@actions/cache": "^1.0.5",
 		"@actions/core": "^1.2.6",
 		"@actions/exec": "^1.0.4",
 		"@actions/github": "^4.0.0",
 		"@actions/io": "^1.0.2",
 		"@rollup/plugin-commonjs": "^17.0.0",
+		"@rollup/plugin-json": "^4.1.0",
 		"@rollup/plugin-node-resolve": "^11.0.0",
 		"builtin-modules": "^3.1.0",
 		"byte-size": "^7.0.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 0224d31..12241c8 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -1,10 +1,11 @@
 devDependencies:
-  '@actions/cache': 1.0.4
+  '@actions/cache': 1.0.5
   '@actions/core': 1.2.6
   '@actions/exec': 1.0.4
   '@actions/github': 4.0.0
   '@actions/io': 1.0.2
   '@rollup/plugin-commonjs': 17.0.0_rollup@2.34.2
+  '@rollup/plugin-json': 4.1.0_rollup@2.34.2
   '@rollup/plugin-node-resolve': 11.0.0_rollup@2.34.2
   builtin-modules: 3.1.0
   byte-size: 7.0.0
@@ -18,7 +19,7 @@ devDependencies:
   xo: 0.35.0
 lockfileVersion: 5.2
 packages:
-  /@actions/cache/1.0.4:
+  /@actions/cache/1.0.5:
     dependencies:
       '@actions/core': 1.2.6
       '@actions/exec': 1.0.4
@@ -31,7 +32,7 @@ packages:
       uuid: 3.4.0
     dev: true
     resolution:
-      integrity: sha512-1grYfbu8P6JDDHc40eOI5tQDRcAxMwq5HBWhaCqEg9o/ixDRZfwPHlQvQAop2ZzFCjF2ns0ENQOIBAH8GNn+zA==
+      integrity: sha512-TcvJOduwsPP27KLmIa5cqXsQYFK2GzILcEpnhvYmhGwi1aYx9XwhKmp6Im8X6DJMBxbvupKPsOntG6f6sSkIPA==
   /@actions/core/1.2.6:
     dev: true
     resolution:
@@ -455,6 +456,15 @@ packages:
       rollup: ^2.30.0
     resolution:
       integrity: sha512-/omBIJG1nHQc+bgkYDuLpb/V08QyutP9amOrJRUSlYJZP+b/68gM//D8sxJe3Yry2QnYIr3QjR3x4AlxJEN3GA==
+  /@rollup/plugin-json/4.1.0_rollup@2.34.2:
+    dependencies:
+      '@rollup/pluginutils': 3.1.0_rollup@2.34.2
+      rollup: 2.34.2
+    dev: true
+    peerDependencies:
+      rollup: ^1.20.0 || ^2.0.0
+    resolution:
+      integrity: sha512-yfLbTdNS6amI/2OpmbiBoW12vngr5NW2jCJVZSBEz+H5KfUJZ2M7sDjk0U6GOOdCWFVScShte29o9NezJ53TPw==
   /@rollup/plugin-node-resolve/11.0.0_rollup@2.34.2:
     dependencies:
       '@rollup/pluginutils': 3.1.0_rollup@2.34.2
@@ -5366,12 +5376,13 @@ packages:
     resolution:
       integrity: sha512-rVksvsnNCdJ/ohGc6xgPwyN8eheCxsiLM8mxuE/t/mOVqJewPuO1miLpTHQiRgTKCLexL4MeAFVagts7HmNZ2Q==
 specifiers:
-  '@actions/cache': ^1.0.4
+  '@actions/cache': ^1.0.5
   '@actions/core': ^1.2.6
   '@actions/exec': ^1.0.4
   '@actions/github': ^4.0.0
   '@actions/io': ^1.0.2
   '@rollup/plugin-commonjs': ^17.0.0
+  '@rollup/plugin-json': ^4.1.0
   '@rollup/plugin-node-resolve': ^11.0.0
   builtin-modules: ^3.1.0
   byte-size: ^7.0.0
diff --git a/rollup.config.js b/rollup.config.js
index a1bb469..03a8137 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -1,11 +1,13 @@
 import commonjs from '@rollup/plugin-commonjs';
 import {nodeResolve} from '@rollup/plugin-node-resolve';
+import json from '@rollup/plugin-json';
 import builtins from 'builtin-modules';
 
 const rollupConfig = {
 	input: 'src/index.js',
 	plugins: [
 		commonjs(),
+		json(),
 		nodeResolve({
 			preferBuiltins: false,
 		}),
diff --git a/src/index.js b/src/index.js
index 22e0d9f..b308e7c 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,6 +1,8 @@
 import * as core from '@actions/core';
 import {context} from '@actions/github';
 import {rmRF} from '@actions/io';
+// import cache from '@actions/cache';
+import crypto from 'crypto';
 import assert from 'assert';
 import fs from 'fs';
 import path from 'path';
@@ -10,6 +12,8 @@ import {sub} from './utils/markdown';
 import comparePackages from './utils/compare-packages';
 import upsertComment from './utils/upsert-comment';
 
+
+console.log('dirname', __dirname);
 // import {createTempDirectory} from '@actions/cache/lib/internal/cacheUtils';
 
 const COMMENT_SIGNATURE = sub('🤖 This report was automatically generated by [pkg-size-action](https://github.com/privatenumber/pkg-size-action/)');
@@ -30,33 +34,75 @@ async function isBaseDiffFromHead(baseRef) {
 	return exitCode !== 0;
 }
 
+const lockFiles = {
+	'package-lock.json': 'npm ci',
+	'yarn.lock': 'yarn install --frozen-lockfile', // yarn is installed on GitHub Actions by default
+	'pnpm-lock.yaml': 'npx pnpm i --frozen-lockfile', // pnpm is not installed on GitHub Actions by default
+};
+
+function findLockFile(directory) {
+	for (const lockFile in lockFiles) { // eslint-disable-line guard-for-in
+		const lockFilePath = path.join(directory, lockFile);
+		if (fs.existsSync(lockFilePath)) {
+			return {
+				lockFilePath,
+				command: lockFiles[lockFile],
+			};
+		}
+	}
+
+	return {
+		lockFilePath: undefined,
+		command: 'npm i',
+	};
+}
+
+const getHash = filePath => new Promise(resolve => {
+	const hash = crypto.createHash('md5');
+	fs.createReadStream(filePath)
+		.on('data', data => hash.update(data))
+		.on('end', () => resolve(hash.digest('hex')));
+});
+
 async function npmCi({cwd} = {}) {
 	if (fs.existsSync('node_modules')) {
 		core.info('Cleaning node_modules');
 		await rmRF(path.join(cwd, 'node_modules'));
 	}
 
-	if (fs.existsSync('package-lock.json')) {
-		core.info('Installing dependencies with npm');
-		return await exec('npm ci', {cwd});
-	}
+	const packageManager = findLockFile(cwd);
 
-	if (fs.existsSync('yarn.lock')) {
-		core.info('Installing dependencies with yarn');
+	console.log(JSON.stringify(packageManager, null, 4));
 
-		// yarn is installed on GitHub Actions by default
-		return await exec('yarn install --frozen-lockfile', {cwd});
-	}
+	// const packageLockHash = await getHash(packageManager.lockFilePath);
 
-	if (fs.existsSync('pnpm-lock.yaml')) {
-		core.info('Installing dependencies with pnpm');
+	// const cached = await cache.saveCache(['node_modules'], packageLockHash);
+	// console.log('cached', JSON.stringify(cached, null, 4));
 
-		// pnpm is not installed on GitHub Actions by default
-		return await exec('npx pnpm i --frozen-lockfile', {cwd});
-	}
+	core.info(`Installing dependencies with ${packageManager.command}`);
+	return await exec(packageManager.command, {cwd});
+
+	// if (fs.existsSync('package-lock.json')) {
+	// 	core.info('Installing dependencies with npm');
+	// 	return await exec('npm ci', {cwd});
+	// }
+
+	// if (fs.existsSync('yarn.lock')) {
+	// 	core.info('Installing dependencies with yarn');
+
+	// 	// yarn is installed on GitHub Actions by default
+	// 	return await exec('yarn install --frozen-lockfile', {cwd});
+	// }
+
+	// if (fs.existsSync('pnpm-lock.yaml')) {
+	// 	core.info('Installing dependencies with pnpm');
+
+	// 	// pnpm is not installed on GitHub Actions by default
+	// 	return await exec('npx pnpm i --frozen-lockfile', {cwd});
+	// }
 
-	core.info('No lock file detected. Installing dependencies with npm');
-	return await exec('npm i', {cwd});
+	// core.info('No lock file detected. Installing dependencies with npm');
+	// return await exec('npm i', {cwd});
 }
 
 async function isFileTracked(filePath) {