Encoding and decoding URLs in Node.js - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is URL encoding and why is it important?

URL encoding converts characters into a format that can be transmitted over the internet. It replaces unsafe ASCII characters with a '%' followed by two hexadecimal digits. This ensures URLs are valid and data is correctly interpreted.

beginner

Which Node.js global functions are used to encode and decode URLs?

encodeURIComponent() is used to encode a URI component by escaping characters. decodeURIComponent() reverses this process, decoding the encoded URI component back to its original form.

intermediate

What is the difference between encodeURI() and encodeURIComponent() in Node.js?

encodeURI() encodes a full URI but leaves characters like '/', ':', and '?' intact. encodeURIComponent() encodes every character that is not a letter, number, or one of a few special characters, making it safer for encoding query parameters.

beginner

How do you decode a URL string in Node.js?

Use decodeURIComponent() to convert an encoded URL component back to its original string. For example, decodeURIComponent('%20') returns a space character.

beginner

Why should you encode query parameters in URLs?

Query parameters may contain special characters like spaces or '&' that can break the URL or cause errors. Encoding ensures these characters are safely transmitted and correctly interpreted by servers and browsers.

Which function should you use to encode a query parameter in Node.js?

A decodeURI()

B encodeURI()

C decodeURIComponent()

D encodeURIComponent()

encodeURIComponent() safely encodes query parameters by escaping all characters that could break the URL.

What does decodeURIComponent('%20') return?

A A space character

B The string '%20'

C An error

D A plus sign (+)

The encoded '%20' represents a space character, so decoding it returns a space.

Which characters does encodeURI() NOT encode?

A All special characters

B Characters like '/', ':', and '?'

C Only letters and numbers

D Spaces only

encodeURI() leaves URI reserved characters like '/', ':', and '?' unencoded to preserve URI structure.

Why is URL encoding necessary?

A To make URLs safe for transmission by replacing unsafe characters

B To shorten URLs

C To encrypt URLs

D To add colors to URLs

Encoding replaces unsafe characters with safe codes so URLs work correctly across the internet.

Which function reverses the encoding done by encodeURIComponent()?

A encodeURI()

B decodeURI()

C decodeURIComponent()

D escape()

decodeURIComponent() decodes strings encoded by encodeURIComponent(), restoring original characters.

Explain how and why you would encode and decode URLs in a Node.js application.

Think about sending data in URLs and how special characters affect them.

Describe the difference between encodeURI() and encodeURIComponent() with examples.

Consider when you want to encode a full link versus just a piece of it.