🟨 Node.js ES6+ Engine

Free Online JavaScript Compiler

Write, run, and evaluate JavaScript & Node.js code online instantly with ES6+ features, JSON parsing, and Monaco editor.

Overview of JavaScript (Node.js) Compiler

JavaScript is the core programming language of the web, powering interactive browser interfaces and high-performance server-side applications via Node.js. Modern JavaScript (ES6+) provides powerful features including Arrow Functions, Promises, Async/Await, Destructuring, and Array methods. Our Online JavaScript Compiler runs Node.js engine in a cloud sandbox, enabling you to test algorithm logic, data transformations, and JS snippets without installing Node.js locally.

How to Use the JavaScript (Node.js) Compiler

  1. Write your JavaScript code into the Monaco editor.
  2. Use console.log() to print outputs to terminal stream.
  3. Click green ▶ Run Code button to execute via Node.js.
  4. Inspect output formatting and JSON objects in the terminal.
  5. Format code with ✨ Format Code for clean spacing.
  6. Share code snippet with peers via 4-digit PIN.

🧪 Tested Code Examples (JavaScript (Node.js))

Example 1: ES6 Arrow Functions & Array Methods

// Online JavaScript / Node.js Compiler
const numbers = [10, 20, 30, 40, 50];

const doubled = numbers.map(num => num * 2);
const filtered = numbers.filter(num => num > 25);

console.log("Original:", numbers);
console.log("Doubled:", doubled);
console.log("Filtered (>25):", filtered);
Expected Output: 
Original: [ 10, 20, 30, 40, 50 ]
Doubled: [ 20, 40, 60, 80, 100 ]
Filtered (>25): [ 30, 40, 50 ]

Code Explanation: Functional array methods map() and filter() process elements cleanly without explicit for loops.

Example 2: Async/Await & Promises

const fetchData = () => {
  return new Promise((resolve) => {
    setTimeout(() => resolve("Data loaded successfully!"), 100);
  });
};

async function main() {
  console.log("Fetching...");
  const result = await fetchData();
  console.log(result);
}

main();
Expected Output: 
Fetching...
Data loaded successfully!

Code Explanation: Demonstrates asynchronous JavaScript execution flow using Promise resolution and async/await syntax.

Example 3: Object Destructuring & JSON

const user = {
  id: 101,
  name: "Sarah",
  role: "Developer",
  skills: ["JS", "React", "Node"]
};

const { name, role } = user;
console.log(`User ${name} is a ${role}`);
console.log("JSON String:", JSON.stringify(user));
Expected Output: 
User Sarah is a Developer
JSON String: {"id":101,"name":"Sarah","role":"Developer","skills":["JS","React","Node"]}

Code Explanation: Template literals (`...`) format variables easily, while JSON.stringify serializes objects.

💡 Try modifying these examples and execute them directly in the compiler editor above!

🛠️ Common JavaScript (Node.js) Compiler Errors & Fixes

⚠️ ReferenceError: X is not defined

Cause: Accessing variable before declaration or misspelling variable name.

How to Fix: Verify variable declaration with const/let before calling.

⚠️ TypeError: X is not a function

Cause: Attempting to call a non-function value or undefined method.

How to Fix: Verify object property type before appending () invocation.

⚠️ SyntaxError: Unexpected token

Cause: Missing closing bracket }, bracket ], or quotes in code block.

How to Fix: Check bracket pairing and template literal backticks.

Frequently Asked Questions (FAQ)

Q: Does this JavaScript compiler run Node.js or browser JS?

It runs Node.js engine on a secure server sandbox, allowing you to test backend JS algorithms, console outputs, and logic.

Q: Are modern ES6+ features supported?

Yes! Arrow functions, destructuring, template literals, async/await, Map/Set, and ES Modules are supported.