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.
You can run these examples directly in your browser's console or in a .js file using Node.js.
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
For a deeper understanding of JavaScript, visit a full 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
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
| Feature | Node.js Support |
|---|---|
| let / const | Yes (since Node 6+) |
| Arrow Functions | Yes (since Node 4+) |
| Destructuring | Yes (since Node 6+) |
| Template Literals | Yes (since Node 4+) |
| Promises | Yes (since Node 0.12+) |
| Async/Await | Yes (since Node 7.6+) |