Check if a string is a hexadecimal color

Accept #rgb, #rgba, #rrggbb and #rrggbbaa.

JavaScript Version 1.0.0 · MIT · .md

function isHexColor(color) { return /^#([0-9A-F]{3}|[0-9A-F]{4}|[0-9A-F]{6}|[0-9A-F]{8})$/i.test(color); }

Input & expected output

"#1c6141"

true

The edge case

"#12345"

false

Know the limits

• Named colors, rgb() and hsl() are not hexadecimal.

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

• Check whether all values are equal — Compare every item with the first using Object.is.
• Check whether an object is empty — Check for own enumerable string keys on a JSON object.
• Check whether an integer is even — Test parity for safe integers, including zero and negative values.