URL Module

URL Module

The URL module allows you to easily parse, construct, and break down web addresses (URLs). When building web servers, you will frequently need to extract specific parts of a URL, such as the path name or query string parameters (like ?user=john&age=25).

The URL module provides an elegant way to dissect these strings without writing messy regular expressions.

1. The URL API

Modern JavaScript uses the global URL class to parse strings. Since it is a global API, you do not even need to require it, though the traditional url module still exists.

// Given a standard web address
const myUrl = new URL('https://www.example.com:8080/products/shoes?color=red&size=10#details');

// Break down the URL into its components:
console.log('Host:', myUrl.host);         // www.example.com:8080
console.log('Hostname:', myUrl.hostname); // www.example.com
console.log('Port:', myUrl.port);         // 8080
console.log('Path:', myUrl.pathname);     // /products/shoes
console.log('Search:', myUrl.search);     // ?color=red&size=10
console.log('Hash:', myUrl.hash);         // #details

2. Working with Query Parameters

The URL class provides a searchParams property, which makes it incredibly simple to read or modify the query parameters attached to the end of a URL.

const myUrl = new URL('https://www.store.com/search?category=electronics&brand=sony');

// Get the value of a specific query parameter
const category = myUrl.searchParams.get('category');
console.log(category); // "electronics"
// Add a new parameter
myUrl.searchParams.append('sort', 'price_desc');
console.log(myUrl.toString()); 
// "https://www.store.com/search?category=electronics&brand=sony&sort=price_desc"