Check if a path is relative

Return true unless the path starts with a slash or backslash, optionally after a drive or scheme.

JavaScript Version 1.0.0 · MIT · .md

function isRelative(path) { return !/^([a-z]+:)?[\\/]/i.test(path); }

Input & expected output

"images/logo.png"

true

The edge case

"C:\\Windows\\notepad.exe"

false

Know the limits

• A scheme without slashes, such as mailto: or data:, still counts as relative. Use the URL-absolute check for URLs.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Capitalize a string — Uppercase the first Unicode code point and preserve the remaining text.
• Reverse a string — Reverse Unicode code points without splitting surrogate pairs.
• Check a palindrome — Compare a string with its code-point reversal.