foreground-text-color-calculator.js

// Returns black or white foreground color depending on the background
var textColor = function (backgroundColor) {
    var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(backgroundColor);
    if (!result) {
        return '#000000';//Happens when not given hex
    }
    var shade = (parseInt(result[1], 16) + parseInt(result[2], 16) + parseInt(result[3], 16)) / 3;
    return shade > 128 ? '#000000' : '#FFFFFF';
}