Install dev dependencies separately

.npmrc

@@ -0,0 +1 @@
+prefer-offline = true

README.md

@@ -9,7 +9,6 @@ This is a Viem and Hardhat 3 project. To get started, please read the instructio
 To start the lab, run:
 
 ```shell
-npm install
 npm run start
 ```
 

exam/common.js

@@ -1,5 +1,8 @@
 import fs from 'fs';
-import { execSync } from 'child_process';
+import { exec, execSync } from 'child_process';
+import { promisify } from 'util';
+
+const execPromise = promisify(exec);
 
 export function installDeps() {
     // check if node_modules exists
@@ -8,7 +11,30 @@ export function installDeps() {
     }
 
     // install dependencies
-    console.log('Installing dependencies...');
-    execSync('npm install', { stdio: 'inherit' });
-    console.log('Dependencies installed');
+    console.log('Installing mandatory dependencies...');
+    execSync('npm install --omit=dev', { stdio: 'inherit' });
+    console.log('Mandatory dependencies installed');
+
+    // install dev dependencies (in the background)
+    console.log(); console.log(); console.log();
+    console.log('Installing dev dependencies...');
+    installDevDeps();
 }
+
+async function installDevDeps(attempt = 1) {
+    try {
+        await execPromise('npm install', { stdio: 'inherit' });
+        console.log('Dev dependencies installed');
+    } catch (error) {
+        console.error('Error installing dev dependencies:', error.message);
+
+        if (attempt < 3) {
+            const retryDelay = 5000 * attempt;
+            console.log(`Retrying in ${Math.round(retryDelay / 1000)} seconds...`);
+            setTimeout(() => installDevDeps(attempt + 1), retryDelay);
+        } else {
+            console.error('Failed to install dev dependencies.');
+            console.error('Please try again manually, by running "npm install" in the project directory.');
+        }
+    }
+}