Node JS Requirements

Quick Start

If you're new to JavaScript, don't worry!

Here are the key concepts you need to know before diving into Node.js.

We'll cover the essentials with simple examples.

JavaScript Fundamentals

Before starting with Node.js, you should be familiar with these JavaScript concepts:

• Variables
• Functions
• Objects
• Arrays
• Asynchronous programming (callbacks, promises, async/await)
• ES6+ features

This page will give short examples of essential JavaScript concepts needed for Node.js development.

For a greater understanding for JavaScipt, visit our JavaScript Tutorial.

Variables and Functions

// Variables (let, const, var)
let name = 'Node.js';
const version = 20;

// Function declaration
function greet(user) {
  return `Hello, ${user}!`;  // Template literal (ES6)
}

// Arrow function (ES6+)
const add = (a, b) => a + b;

console.log(greet('Developer')); // Hello, Developer!
console.log(add(5, 3));         // 8

Objects and Arrays

// Object
const user = {
  name: 'Alice',
  age: 25,
  greet() {
    console.log(`Hi, I'm ${this.name}`);
  }
};

// Array
const colors = ['red', 'green', 'blue'];

// Array methods (ES6+)
colors.forEach(color => console.log(color));
const lengths = colors.map(color => color.length);

Asynchronous JavaScript

// 1. Callbacks (traditional)
function fetchData(callback) {
  setTimeout(() => {
    callback('Data received!');
  }, 1000);
}

// 2. Promises (ES6+)
const fetchDataPromise = () => {
  return new Promise((resolve) => {
    setTimeout(() => resolve('Promise resolved!'), 1000);
  });
};

// 3. Async/Await (ES8+)
async function getData() {
  const result = await fetchDataPromise();
  console.log(result);
}

getData(); // Call the async function

Destructuring & Template Literals (ES6+)

const { name } = user;
console.log(`Hello, ${name}!`);

Key JavaScript Concepts

• Variables: let (mutable), const (immutable), var (legacy)
• Functions: Regular, arrow functions, and methods
• Objects & Arrays: Data structures for organizing data
• Modules: require() (CommonJS) and import/export (ES6)
• Error Handling: try/catch blocks

Quick Reference Table