Converting decrypt function from VB to JS-CodePudding

I have a function coded in vb. I am trying to convert it to Javascript

Public Function Decrypt(ByVal s As String) As String
    Dim Total As String
    Dim Tmp As String
    For i = 1 To Len(s)
        Tmp = Mid(s, i, 1)
        Tmp = Asc(Tmp) - 15
        Tmp = Chr(Tmp)
        Total = Total & Tmp
    Next i
    Decrypt = Total
End Function

So far this is what I have

function decrypt( s ) {
  let tmp = ''
  let total = ''

  for ( let i = 1; i < s.length; i   ) {
    tmp = s.substring(i, 1)
    tmp = tmp.charCodeAt(0) - 15
    tmp = String.fromCharCode(tmp)
    total  = total   tmp
  }
  return total
}

Im getting the error RangeError: Invalid string length at line total = total tmp

How can I fix this function please

CodePudding user response：

This is exact translation. Tested in excel VBA.

function decrypt(s) {
  var total = ""
  for (var i = 1; i <= s.length; i  ) {
    var tmp = s.substring(i - 1, i);
    total  = String.fromCharCode(tmp.charCodeAt(0) - 15);
  }
  return total
}

console.log(decrypt("hello"))