JavaScript & TypeScript Editor: Write Modern Web Code

Write modern JavaScript and TypeScript code with our online editor. Full syntax highlighting, IntelliSense, and instant browser execution make it perfect for web development and learning.

JavaScript vs TypeScript

JavaScript

• Dynamic typing - flexible but can lead to runtime errors
• No compilation step - runs directly in browser
• Widely supported - works everywhere
• Great for quick prototyping

TypeScript

• Static typing - catch errors before runtime
• Compiles to JavaScript
• Better IDE support with IntelliSense
• Ideal for large-scale applications

Modern JavaScript Features

Our editor supports all modern JavaScript features:

ES6+ Syntax

// Arrow functions
const greet = (name) => `Hello, ${name}!`;

// Destructuring
const { name, age } = user;
const [first, ...rest] = items;

// Template literals
const message = `User ${name} is ${age} years old`;

// Async/await
async function fetchData() {
  const response = await fetch('/api/data');
  return response.json();
}

Classes and Modules

class User {
  constructor(name, email) {
    this.name = name;
    this.email = email;
  }
  
  greet() {
    return `Hello, I'm ${this.name}`;
  }
}

// Export/import (ES modules)
export default User;
import User from './user.js';

TypeScript Features

• Type Annotations: Define types for variables, functions, and classes
• Interfaces: Define object shapes and contracts
• Generics: Write reusable, type-safe code
• Union Types: Combine multiple types
• Type Inference: Automatic type detection

TypeScript Example

interface User {
  name: string;
  age: number;
  email?: string;  // Optional property
}

function createUser(name: string, age: number): User {
  return { name, age };
}

// Generic function
function getFirst<T>(items: T[]): T | undefined {
  return items[0];
}

Code Execution

Our editor can execute JavaScript and TypeScript code directly in your browser:

• Run code instantly without compilation
• See output and errors immediately
• Test API calls and async operations
• Debug with console.log statements

Best Practices

• Use const/let instead of var
• Prefer arrow functions for callbacks
• Use async/await over promises.then()
• Enable strict mode for better error detection
• Use TypeScript for type safety in larger projects

Start writing JavaScript and TypeScript code with our JavaScript/TypeScript Editor!