JSFiddle - React, Tailwind, and code Playground

JavaScript

var items = [{
  market_hash_name: "item_1"
}, {
  market_hash_name: "item_2"
}, {
  market_hash_name: "item_3"
}, {
  market_hash_name: "item_4"
}, {
  market_hash_name: "item_3"
}, {
  market_hash_name: "item_4"
}];

var g_ItemName = ["item_1", "item_4", "item_5", "item_4", "item_4"];
var otvet = null;
var itemsClone = items.slice(0);

for (var j = 0; j < g_ItemName.length; j++) {
  var sendItemName = g_ItemName[j];
  console.log('sendItemName : ', sendItemName);
  if (typeof sendItemName != 'undefined') {
    if (innova(sendItemName, itemsClone)) {
      document.write('Вещь "' + sendItemName + '" найдена в инвентаре<br>');
      otvet = true;
    } else {
      document.write('Вещь "' + sendItemName + '" не найдена в инвентаре<br>');
      otvet = false;
    }
    document.write("Длина массива для поиска: " + itemsClone.length + "<br>");
  }
}

function innova(name_sends, itemsClone) {
  for (var a = 0; a < itemsClone.length; a++) {
    ft = itemsClone;
    if (name_sends === itemsClone[a].market_hash_name) {
      itemsClone.splice(a, 1);
      return true;
    }
  }
  return false;
}

for (var i = 0; i < items.length; i++) {
  document.write('items market_hash_name: ' + items[i].market_hash_name + '<br>');
}