Get Random Color with Random Opacity (Useful for Charts)

GetRandomColorWithRandomOpacity.js

const hexColors = [
  '#3366CC',
  '#DC3912',
  '#FF9900',
  '#109618',
  '#990099',
  '#3B3EAC',
  '#0099C6',
  '#DD4477',
  '#66AA00',
  '#B82E2E',
  '#316395',
  '#994499',
  '#22AA99',
  '#AAAA11',
  '#6633CC',
  '#E67300',
  '#8B0707',
  '#329262',
  '#5574A6',
  '#3B3EAC',
  '#ff6384',
  '#36a2eb',
  '#ffce56',
]

export function getRandomColorWithRandomOpacity(shuffled = false, randomOpacity = false, minOpacity = 0.4, maxOpacity = 1) {
  const colorArr = !shuffled ? [...hexColors] : suffledArray([...hexColors]);
  return colorArr
    .map(color =>
      !randomOpacity
        ? hex2rgb(color)
        : hex2rgb(color, getRandomOpacity(minOpacity, maxOpacity))
    );
}

function getRandomOpacity(min = 0.4, maxOpacity = 1) {
  return Math.min(Math.max(getRandomArbitrary(min - 0.1, maxOpacity + 0.1), min), maxOpacity);
}

function getRandomArbitrary(min, max) {
  return Math.random() * (max - min) + min;
}

// modified from https://stackoverflow.com/a/36048299/6120338
function hex2rgb(hex, opacity?) {
  hex = hex.trim();
  hex = hex[0] === '#' ? hex.substr(1) : hex;
  const bigInt = parseInt(hex, 16);
  const h = [];
  if (hex.length === 3) {
    h.push((bigInt >> 4) & 255);
    h.push((bigInt >> 2) & 255);
  } else {
    h.push((bigInt >> 16) & 255);
    h.push((bigInt >> 8) & 255);
  }
  h.push(bigInt & 255);
  if (opacity) {
    h.push(opacity);
  }
  return 'rgb(' + h.join() + ')';
}

// taken from https://stackoverflow.com/a/46545530/6120338
function suffledArray(arr = []) {
  return arr
    .map((a) => ({ sort: Math.random(), value: a }))
    .sort((a, b) => a.sort - b.sort)
    .map((a) => a.value);
}