Javascript in array then return key

I’m trying to find the ean codes from below array in the variantCodesObject. That part I can get working however I’m struggeling to return the key from the variantCodesObject.

cart array
[
  {"ean": "7350038272416","quantity": 1},
  {"ean": "7350038270276","quantity": 3}
]


variantCodesObject array

[
 { 261584049: "7350038272416" },
 { 261583813: "7350038274120" },
 { 261583424: "7350038270276" },
 { 261122928: "210000018685" },
]

cart.forEach(function (cartItem){    
  var ean = cartItem.ean;
  var qty = cartItem.quantity;

  if(variantCodesObject.indexOf(ean)){
    
    makeSomeRequest(??, qty) //How do I get the key of the found EAN's here?

  }

})

In above example how do I get for ean 7350038272416 the key value 261584049?

I tried something like this:

variantCodesObject.forEach(function(item){
          if(item.indexOf(ean)){
            Object.keys(item).forEach(function(key) {
              console.log("key:" + key + "value:" + item[key]);
            });
          }
        });

But that returns the full variantCodesObject.

Answer

You can do this by checking the value of the object in the variantCodesObject against the .ean property on each cart item. If it matches, do whatever you’d like with the key

cart = [
  {"ean": "7350038272416","quantity": 1},
  {"ean": "7350038270276","quantity": 3}
]


variantCodesObject = [
 { 261584049: "7350038272416" },
 { 261583813: "7350038274120" },
 { 261583424: "7350038270276" },
 { 261122928: "210000018685" },
]


cart.forEach(item => {
  variantCodesObject.forEach(obj => {
    Object.entries(obj).forEach(([key, value]) => {
      if (value === item.ean) {
        console.log(key);
      }
    });
  })
})