Some useful color methods to be used as modular functions. Credit where credit's due: If not my own, the source is given in comments.

checkColorBrightness.js

// Check for color darkness. Returns false of dark'ish, true if bright
function checkForBrightness(arr) {
  let sortedArr = arr.sort;
  return (sortedArr[0] < 150 && sortedArr[1] < 80 && sortedArr[2] < 80) ?
    false : true
}

randomHex.js

// Create a random hex number
function createRandomColor() {
  let rNum = Math.ceil(Math.random() * 16777215).toString(16);
  return '#'.concat(rNum);
}

rgbArrToRgbString.js

// Convert rgb arr to rgb string
function rgbArrToStr(rgbArr) {
  let rgbCols = rgbArr.join(',');
  let rgbStr = 'rgb(' + rgbCols + ')';
  return rgbStr;
}

rgbCheck.js

// Check if string has rgb format
function rgbCheck(color) {
  // Source for RegExp: https://gist.github.com/sethlopezme/d072b945969a3cc2cc11
  let regExpRgb = /^rgb\((0|255|25[0-4]|2[0-4]\d|1\d\d|0?\d?\d),(0|255|25[0-4]|2[0-4]\d|1\d\d|0?\d?\d),(0|255|25[0-4]|2[0-4]\d|1\d\d|0?\d?\d)\)$/;
  return regExpRgb.test(color);
}

rgbStringToRgbArr.js

// Convert rgb string to rgb arr
function rgbStrToArr(rgbStr) {
  let rgbCols = rgbStr.slice(4, (rgbStr.length - 1));
  let rgbArr = rgbCols.split(',');
  let rgbArrNum = rgbArr.map(Number);
  return rgbArrNum;
}

rgbToHex.js

function rgbToHex(r, g, b) {
  return "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
}