diff --git a/install.js b/install.js
index 114bc7dc1144b..8555af326dc0a 100644
--- a/install.js
+++ b/install.js
@@ -14,45 +14,6 @@
  * limitations under the License.
  */
 
-const fs = require('fs');
-const path = require('path');
-const child_process = require('child_process');
-const {promisify} = require('util');
-
-const fsAccess = promisify(fs.access);
-const exec = promisify(child_process.exec);
-
-const fileExists = async filePath => fsAccess(filePath).then(() => true).catch(() => false);
-
-/*
- * Now Puppeteer is built with TypeScript, we need to ensure that
- * locally we have the generated output before trying to install.
- *
- * For users installing puppeteer this is fine, they will have the
- * generated lib/ directory as we ship it when we publish to npm.
- *
- * However, if you're cloning the repo to contribute, you won't have the
- * generated lib/ directory so this script checks if we need to run
- * TypeScript first to ensure the output exists and is in the right
- * place.
- */
-async function compileTypeScript() {
-  return exec('npm run tsc').catch(err => {
-    console.error('Error running TypeScript', err);
-    process.exit(1);
-  });
-}
-
-async function ensureLibDirectoryExists() {
-  const libPath = path.join(__dirname, 'lib');
-  const libExists = await fileExists(libPath);
-  if (libExists) return;
-
-  logPolitely('Compiling TypeScript before install...');
-  await compileTypeScript();
-}
-
-
 /**
  * This file is part of public API.
  *
@@ -62,13 +23,16 @@ async function ensureLibDirectoryExists() {
  * still possible to install a supported browser using this script when
  * necessary.
  */
+
+const compileTypeScriptIfRequired = require('./typescript-if-required');
+
 const supportedProducts = {
   'chrome': 'Chromium',
   'firefox': 'Firefox Nightly'
 };
 
 async function download() {
-  await ensureLibDirectoryExists();
+  await compileTypeScriptIfRequired();
 
   const downloadHost = process.env.PUPPETEER_DOWNLOAD_HOST || process.env.npm_config_puppeteer_download_host || process.env.npm_package_config_puppeteer_download_host;
   const puppeteer = require('./index');
diff --git a/package.json b/package.json
index 205e77cc0a917..26419672b4ae9 100644
--- a/package.json
+++ b/package.json
@@ -18,6 +18,7 @@
     "debug-unit": "node --inspect-brk test/test.js",
     "test-doclint": "mocha --config mocha-config/doclint-tests.js",
     "test": "npm run tsc && npm run lint --silent && npm run coverage && npm run test-doclint && npm run test-types",
+    "prepare": "node typescript-if-required.js",
     "prepublishOnly": "npm run tsc",
     "dev-install": "npm run tsc && node install.js",
     "install": "node install.js",
diff --git a/typescript-if-required.js b/typescript-if-required.js
new file mode 100644
index 0000000000000..4b3a3406d72c5
--- /dev/null
+++ b/typescript-if-required.js
@@ -0,0 +1,59 @@
+/**
+ * Copyright 2020 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const child_process = require('child_process');
+const path = require('path');
+const fs = require('fs');
+const {promisify} = require('util');
+
+const exec = promisify(child_process.exec);
+const fsAccess = promisify(fs.access);
+
+const fileExists = async filePath => fsAccess(filePath).then(() => true).catch(() => false);
+/*
+
+ * Now Puppeteer is built with TypeScript, we need to ensure that
+ * locally we have the generated output before trying to install.
+ *
+ * For users installing puppeteer this is fine, they will have the
+ * generated lib/ directory as we ship it when we publish to npm.
+ *
+ * However, if you're cloning the repo to contribute, you won't have the
+ * generated lib/ directory so this script checks if we need to run
+ * TypeScript first to ensure the output exists and is in the right
+ * place.
+ */
+async function compileTypeScript() {
+  return exec('npm run tsc').catch(err => {
+    console.error('Error running TypeScript', err);
+    process.exit(1);
+  });
+}
+
+async function compileTypeScriptIfRequired() {
+  const libPath = path.join(__dirname, 'lib');
+  const libExists = await fileExists(libPath);
+  if (libExists) return;
+
+  console.log('Puppeteer:', 'Compiling TypeScript...');
+  await compileTypeScript();
+}
+
+// It's being run as node typescript-if-required.js, not require('..')
+if (require.main === module)
+  compileTypeScriptIfRequired();
+
+module.exports = compileTypeScriptIfRequired;