Convert a rgba/rgb color to vec4. Convert vec4 color to rgba

rgbaToVec.js

const normalize = (min, max, value) => {
  if (value < min) return min
  else if (value > max) return max
  else return value
}

const splitChannels = (color, split) => {
  color = color.replace(split, '').replace(')', '').trim()

  let channels = color.split(',')

  if (channels.length < 3 || channels.length > 4) {
    throw new Error(`${color} is not a valid rgb(a) color`)
  }

  return channels
}

const getChannels = (color) => {
  let alpha = false
  if (color.startsWith('r')) {
    if (color.startsWith(`rgba(`)) alpha = true
    else if (color.startsWith(`rgb(`)) alpha = false

    const split = alpha ? `rgba(` : `rgb(`
    return splitChannels(color, split)
  } else if (color.startsWith('v')) { // Vector to rgb
    if (color.startsWith(`vec4(`)) alpha = true
    else if (color.startsWith(`vec3(`)) alpha = false

    const split = alpha ? `vec4(` : `vec3(`
    return splitChannels(color, split)
  } else {
    throw new Error(`${color} is not a valid rgb(a) color`)
  }
}

const vecToRgb = (color) => {
  let channels = getChannels(color)
  channels = channels.map(c => parseFloat(c)).map(c => normalize(0, 1, c))
  let [r, g, b, a] = []

  if (channels.length === 4) {
    [r, g, b, a] = channels
  } else {
    [r, g, b, a = 1] = channels
  }

  const rgb = [r, g, b].map(c => Math.round(c * 255))
  const alpha = normalize(0, 1, a)

  return `rgba(${rgb[0]}, ${rgb[1]}, ${rgb[2]}, ${alpha})`
}

const rgbToVec = (color) => {
  let channels = getChannels(color)
  channels = channels.map(c => parseFloat(c)).map(c => normalize(0, 255, c))

  let [r, g, b, a] = []

  if (channels.length === 4) {
    [r, g, b, a] = channels
  } else {
    [r, g, b, a = 1] = channels
  }

  const rgb = [r, g, b].map(c => Math.round(c / 255 * 10) / 10)
  const alpha = normalize(0, 1, a)

  return `vec4(${rgb[0]}, ${rgb[1]}, ${rgb[2]}, ${alpha})`
}

export default {
  vecToRgb,
  rgbToVec
}