NodejsHow-ToBeginner · 3 min read

How to Encode URL in Node.js: Simple Guide with Examples

In Node.js, you can encode URLs using the built-in encodeURIComponent() function to safely encode parts of a URL. For full URLs, you can use the URL class to construct and encode URLs properly.

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Syntax

The main methods to encode URLs in Node.js are:

encodeURIComponent(string): Encodes a URI component by escaping characters that have special meaning.
encodeURI(string): Encodes a full URI but leaves some characters like :/?# intact.
new URL(input, base): Creates a URL object that automatically encodes components when you set them.

javascript

encodeURIComponent(component)
encodeURI(uri)
const url = new URL(input, base);

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Example

This example shows how to encode a query parameter safely using encodeURIComponent and how to build a full URL using the URL class.

javascript

const searchTerm = 'Node.js & URL encoding';

// Encode a query parameter
const encodedTerm = encodeURIComponent(searchTerm);
console.log('Encoded query parameter:', encodedTerm);

// Build a full URL with encoded query
const baseUrl = 'https://example.com/search';
const url = new URL(baseUrl);
url.searchParams.set('q', encodedTerm);
console.log('Full encoded URL:', url.toString());

Output

Encoded query parameter: Node.js%20%26%20URL%20encoding Full encoded URL: https://example.com/search?q=Node.js%20%26%20URL%20encoding

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Common Pitfalls

Common mistakes include:

Using encodeURI() to encode query parameters, which does not encode characters like & and =, causing errors.
Double encoding already encoded strings, which leads to incorrect URLs.
Not encoding user input before adding it to URLs, risking broken URLs or security issues.

javascript

const wrong = encodeURI('Node.js & URL encoding');
console.log('Wrong encoding:', wrong);

const right = encodeURIComponent('Node.js & URL encoding');
console.log('Right encoding:', right);

Output

Wrong encoding: Node.js%20&%20URL%20encoding Right encoding: Node.js%20%26%20URL%20encoding

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Quick Reference

Function/Class	Purpose	When to Use
encodeURIComponent(string)	Encodes individual URI components	Encode query parameters or path segments
encodeURI(string)	Encodes full URI but leaves some chars intact	Encode full URLs without query parameters
URL class	Builds and encodes full URLs	Construct URLs with multiple parts safely

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Key Takeaways

Use encodeURIComponent() to safely encode query parameters or parts of URLs.

Use the URL class to build and encode full URLs with multiple components.

Avoid encodeURI() for query parameters as it leaves some characters unencoded.

Never double encode strings; encode only once before using in URLs.

Always encode user input before adding it to URLs to prevent errors and security issues.