Convert 3 digits color to 6 digits color

Double each digit of a #rgb color.

JavaScript Version 1.0.0 · MIT · .md

function toFullHexColor(color) { return `#${(color.startsWith('#') ? color.slice(1) : color).split('').map(digit => `${digit}${digit}`).join('')}`; }

Input & expected output

"#16a"

"#1166aa"

The edge case

"fff"

"#ffffff"

Know the limits

• Input must be three hexadecimal digits, with or without #.

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

• Convert Celsius to Fahrenheit — Apply the temperature conversion without rounding the result.
• Convert hex to RGB — Expand #rgb if needed and read the red, green and blue channels.
• Convert URL parameters to object — Read a query string into an object; repeated keys become arrays.