Javascript-检查数组前瞻匹配

[1, 2, 2.1, 3, 4, 4.1 ] //...etc

我想做的是在一个调用中将幻灯片的所有细节传递给幻灯片API。为此,我想在创建“2”幻灯片的调用中传递“2.1”数组。为此,我需要对阵列进行前瞻。

这是我用来测试的代码和我的 JSFiddle

var foo = new Array();
var firstProduct;
var secondProduct = "";
var order;
foo = [
  [1, "one2", "one3"],
  [2, "two2", "two3"],
  [2.1, "two21", "two31"],
  [3, "three2", "three3"]
];
for (var i = 0; i < foo.length; i++) {
  firstProduct = foo[i][0];
  if (foo[i][0] <= foo.length) {
    secondProduct = foo[i + 1][0];
    if (typeof secondProduct !== 'undefined' && Math.floor(firstProduct) == Math.floor(secondProduct)) {
      alert("Match " + firstProduct + " " + secondProduct);
      i++;
    }
    else {
        alert("No match - firstProduct" + firstProduct);
      }
   }
   else {
      alert("last " + firstProduct);
    }
}

VM3349:59未捕获类型错误:无法读取未定义的属性“0” 在窗口。空载(VM3349:59)