postcss/functions.js

const postcssFunctions = {
  // takes the custom property defined by a color defining mixin, along
  // with an alpha value and returns the derived css hsla() function.
  alpha(name, alpha) {
    const hue = `var(${name}__h)`;
    const saturation = `var(${name}__s)`;
    const lightness = `var(${name}__l)`;
    return `hsla(${hue}, ${saturation}, ${lightness}, ${alpha})`;
  },
  spacer(number = 1) {
    return `calc(var(--spacer-height, 1.5rem) * ${number})`;
  },
};

module.exports = postcssFunctions;