colors.js

// https://www.reddit.com/r/learnprogramming/comments/3456xv/convert_rgb_color_to_wavelengthfrequency/
// https://www.alanzucconi.com/2015/09/30/colour-sorting/

const WHITE_STRING = parseInt( 'FFFFFF', 16 )
const NUMBER_OF_COLORS = 50
const genRandomInt = (min, max) => Math.floor(Math.random() * (max - min)) + min

const getHueFromRGB = ({ red, green, blue }) => {

  const min = Math.min(Math.min(red, green), blue);
  const max = Math.max(Math.max(red, green), blue);

  if (min === max) {
    return 0;
  }

  let hue = 0
  if (max === red) {
    hue = (green - blue) / (max - min);

  } else if (max === green) {
    hue = 2 + (blue - red) / (max - min);

  } else {
    hue = 4 + (red - green) / (max - min);
  }

  hue = hue * 60;
  if (hue < 0) hue = hue + 360;

  return Math.round(hue);
}

function hexToRgb(hex) {
  var result = /([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  return {
      red: parseInt(result[1], 16),
      green: parseInt(result[2], 16),
      blue: parseInt(result[3], 16)
  }
}

const getWavelengthFromHue = (hue) => {
  return (891,42 - hue) / 1.37
}
const waveLengthFromHEX = (hex) => {
  const rgb = hexToRgb(hex)
  const hue = getHueFromRGB(rgb)
  const waveLength = getWavelengthFromHue(hue)
  return waveLength
}

const printColor = color => {
  console.log( `%c                    ${color}`, `background-color: #${color}` )
}

let randomColors = []

console.log ('===============RANDOM COLORS==================')
for (let i = 0; i <= NUMBER_OF_COLORS; i+=1) {
  const number = genRandomInt(0, WHITE_STRING)
  const color = (number).toString(16).padStart(6, '0').toUpperCase()
  randomColors.push(color)
  printColor(color)
}

randomColors.sort((a, b) => {
  return waveLengthFromHEX(a) - waveLengthFromHEX(b)
})

console.log ('')
console.log ('')
console.log ('')
console.log ('')
console.log ('===============SORTED COLORS==================')

randomColors.forEach(color => {
  printColor(color)
})