hex-to-hsl.mjs

export default function HEXToHSL(H) {
  let r = 0
  let g = 0
  let b = 0

  if (H.length == 4) {
    r = "0x" + H[1] + H[1]
    g = "0x" + H[2] + H[2]
    b = "0x" + H[3] + H[3]
  }
  else if (H.length == 7) {
    r = "0x" + H[1] + H[2]
    g = "0x" + H[3] + H[4]
    b = "0x" + H[5] + H[6]
  }

  r /= 255
  g /= 255
  b /= 255

  let cmin = Math.min(r,g,b)
  let cmax = Math.max(r,g,b)
  let delta = cmax - cmin
  let h = 0
  let s = 0
  let l = 0

  if (delta == 0)
    h = 0
  else if (cmax == r)
    h = ((g - b) / delta) % 6
  else if (cmax == g)
    h = (b - r) / delta + 2
  else
    h = (r - g) / delta + 4

  h = Math.round(h * 60)

  if (h < 0)
    h += 360

  l = (cmax + cmin) / 2
  s = delta == 0 ? 0 : delta / (1 - Math.abs(2 * l - 1))
  s = +(s * 100).toFixed(1)
  l = +(l * 100).toFixed(1)

  return { h, s, l }
}