How to write JSON into splice

Question

I currently trying to splice an array one by one until empty. I wonder if I add JSON into it, will it work? Or is there any other way to splice an array one by one per attempt. Below is my script.

var promoCode = '';
var bg1 = 'https://cdn.pixabay.com/photo/2020/06/01/22/23/eye-5248678__340.jpg';
var bg2 = 'http://farm5.static.flickr.com/4017/4717107886_dcc1270a65_b.jpg';
var bg3 = 'http://images6.fanpop.com/image/photos/41500000/adorable-puppies-cute-puppies-41538743-590-393.jpg';


var bgArr = [bg1, bg2, bg3];
for(var i = bgArr.length-1;i>=0;i--){
  selectBG = bgArr.splice(Math.floor(Math.random()*bgArr.length), 1)[0];
  console.log(selectBG);
}



if (selectBG === bg1) {
  promoCode = 'SCRATCH400';
  
} else if (selectBG === bg2) {
  promoCode = 'SCRATCH500';
  
} else if (selectBG === bg3) {
  promoCode = 'SCRATCH600';
 
} else if (bgArr.length === 0) {
  alert("No more voucher, back to main website");
  window.location = 'https://www.google.com/';
}