hsl-rgb/index.js

Convert hsl colors to rgb colors

const hue = (p, q, t) => {
  if (t < 0) t += 1;
  if (t > 1) t -= 1;
  if (t < 1/6) return p + (q - p) * 6 * t;
  if (t < 1/2) return q;
  if (t < 2/3) return p + (q - p) * (2/3 - t) * 6;

  return p;
}

const hslRgb = (h, s, l) => {
  let r, g, b;
  h = h / 360;

  if (s == 0) {
    r = g = b = l;
  } else {
    const q = l < 0.5 ? l * (1 + s) : l + s - l * s;
    const p = 2 * l - q;

    r = hue(p, q, h + 1/3);
    g = hue(p, q, h);
    b = hue(p, q, h - 1/3);
  }

  return [
    Math.max(0, Math.min(Math.round(r * 255), 255)),
    Math.max(0, Math.min(Math.round(g * 255), 255)),
    Math.max(0, Math.min(Math.round(b * 255), 255)) 
  ];
};

module.exports = hslRgb;