code check :i expect IndexPlus is 2 but it seems it becom 1+1=11,why?

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description :

i expect the indexPlus 2 but it comes 11，what is wrong? and why?
see it in line 28 .

code:

var inputArr = [1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6, 0]
console.log('before', inputArr)
var arr = []
//先遍历inputArr确定0的位置
for (key in inputArr) {
  if (inputArr[key] === 0) {
    arr.push(key)
  }
}
//将0移到数组最后面，通过位置交换实现
for (value of arr) {
  for (i = value; i < inputArr.length - 1; i++) {
    swap(i, i + 1)
  }
}

function swap(index, indexPlus) {
  var temp = inputArr[index]
  inputArr[index] = inputArr[indexPlus]
  inputArr[indexPlus] = temp
}
console.log('after', inputArr)