How to get the background color of an element using javascript

index.js

function getBgColor(e, pseudo) {
  var transparent = 'rgba(0, 0, 0, 0)'
  if (!e) {
    return transparent
  }
  
  var currentBgColor = window.getComputedStyle(e, pseudo).backgroundColor
  
  if (currentBgColor === transparent) {
    getBgColor(e.parentElement)
  }
    
  return currentBgColor
}