isDark.js

isDark.js is the smallest code to know if any color is dark or light. 538 bytes gzipped // 727 bytes minified. No dependency and crossbrowser (IE9+). Will be adapted for Node.JS.

isDark.js supports every color :

• HSL() and HSLA()
• RGB() and RGBA() (including with percentage values)
• Hexadecimal (#RGB, #RGBA, #RRGGBB and #RRGGBBAA)
• Every keyname, including rebeccapurple and transparent (return both true)

isDark.js, however, don't detect illegal and deprecated values. It doesn't support currentColor.

Security

Security issues has been solved. Even if the code uses eval, it is safe.

How to use

Just call window.isDark("black") // true.

Examples

isDark("black");
isDark("white");
isDark("salmon");
isDark("rgb(200 24 37)");
isDark("rgba(200, 24, 37)");
isDark("rgb(0% 0% 0%)");
isDark("hsl(0 50% 100%)");
isDark("hsla(0, 50%, 100%, 1)");
isDark("#FFF");
isDark("FFF");
isDark("#FF0000");
isDark("FF000000");

isLight()

function isLight(color){
    return !isDark(color);
}

License

This code is under MIT License.

Ressources

About colors and brightness :

• Calculating the Perceived Brightness of a Color (NbdTech)
• Techniques For Accessibility Evaluation And Repair Tools (W3C)
• CSS4 Color Module Level 4 (W3C)

About conversion (all conversion functions were modified) :

• Converting HSL to RGB
• One-liner Hex to RGB
• Short Hex to long hex