Flash cards
Review the key moves
What is the main idea behind Node.js JavaScript Requirements?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
// Variables (___, const, var)Put the learning moves in the order that makes the concept easiest to apply.
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
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)); // 8Objects 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 functionDestructuring & 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