JAVASCRIPT
Validate Hex Color Code Format
Ensure user input for colors is in a valid hexadecimal format (e.g., #RRGGBB, #RGB) using a concise JavaScript regex pattern, ideal for form validation.
function isValidHexColor(hexColor) {
const hexRegex = /^#([0-9a-fA-F]{3}){1,2}$/;
return hexRegex.test(hexColor);
}
// Example usage:
console.log(isValidHexColor('#FFF')); // true
console.log(isValidHexColor('#FFFFFF')); // true
console.log(isValidHexColor('#abc')); // true
console.log(isValidHexColor('#abcdef')); // true
console.log(isValidHexColor('FFF')); // false (missing #)
console.log(isValidHexColor('#FFG')); // false (invalid character)
console.log(isValidHexColor('#FFFFFFF'));// false (too long)
How it works: This regex `^#([0-9a-fA-F]{3}){1,2}$` validates hex color codes. `^#` asserts the start of the string with a hash. `([0-9a-fA-F]{3})` matches three hexadecimal characters (0-9, a-f, A-F). `{1,2}` means this group can appear once (for `#RGB`) or twice (for `#RRGGBB`). `$` asserts the end of the string, ensuring the entire input matches the pattern.