aliascss/lib/compilers/color.js

AliasCSS is a CSS post processor.

// custom.color will be provided {primary:'#2d3f3e....}
export default function color(color, custom) {
    if (color.match(/^--[a-zA-Z]/))
        return `var(${color})`;
    color = color.replace(/^[-]/, '');
    if (custom.hasOwnProperty('colors') && typeof custom.colors === 'object') {
        if (custom.colors.hasOwnProperty(color))
            return custom.colors[color];
    }
    // hexadecimal =+ alpha 00-ff
    if (/^[0-9a-fA-F]{3,8}$/.test(color)) {
        return `#${color}`;
        // Name
    }
    else if (/^[a-zA-Z]+$/.test(color)) {
        return color;
        // rgb/a in number
    }
    else if (/^[0-9]{9}/.test(color)) {
        if (color.length === 9)
            return `rgb(${color.replace(/([\d]{3})([\d]{3})([\d]{3})/, '$1,$2,$3')})`;
        else
            return `rgba(${color
                .replace(/([\d]{3})([\d]{3})([\d]{3})([\d]+)/, '$1,$2,$3,$4')
                .replace('d', '.')
                .replace('p', '%')})`;
    }
    else if (/^([\d]{3})([\d]{1,3}p)([\d]{1,3}p)/.test(color)) {
        if (/^([\d]{3})([\d]{1,3}p)([\d]{1,3}p)$/.test(color))
            return 'hsl(' + color.replace(/^([\d]{1,3})([\d]{1,3}p)([\d]{1,3}p)/, '$1,$2,$3').replace(/p/g, '%') + ')';
        else
            return ('hsla(' +
                color
                    .replace(/^([\d]{1,3})([\d]{1,3}p)([\d]{1,3}p)([\d]+)/, '$1,$2,$3,$4')
                    .replace('d', '.')
                    .replace(/p/g, '%') +
                ')');
    }
    else if (/^([\d]{1,3}p)([\d]{1,3}p)([\d]{1,3}p)/.test(color)) {
        if (/^([\d]{1,3}p)([\d]{1,3}p)([\d]{1,3}p$)/.test(color))
            return 'rgb(' + color.replace(/^([\d]{1,3}p)([\d]{1,3}p)([\d]{1,3}p)/, '$1,$2,$3').replace(/p/g, '%') + ')';
        else
            return ('rgba(' +
                color
                    .replace(/^([\d]{1,3}p)([\d]{1,3}p)([\d]{1,3}p)([\d]+)/, '$1,$2,$3,$4')
                    .replace('d', '.')
                    .replace(/p/g, '%') +
                ')');
    }
    else if (/^(rgb|hsl|hsla|rgba)-/.test(color)) {
        const match = color.match(/^(rgb|hsl|hsla|rgba)-/);
        const colorFunc = match ? match[1] : '';
        if (color.replace(colorFunc, '').match(/^--/))
            return `${colorFunc}(var(${color.replace(colorFunc, '')}))`;
        return `${colorFunc}(${color.replace(colorFunc, '').replace(/^-/, '').replace(/-/g, ',').replace('d', '.')
            .replace(/p/g, '%')})`;
    }
    else {
        return;
    }
}