Javascript not equal and OR

Question

This looks a simple code but not sure what I am doing wrong here.

var data = "[{\"Id\":\"01\",\"Name\":\"01- Alabama\"},{\"Id\":\"02\",\"Name\":\"02- Arizona\"},{\"Id\":\"03\",\"Name\":\"03- Arkansas\"}]";

 var myJson = JSON.parse(data);
 for (var key in myJson) {
   var item = {
   Id: myJson[key].Id,
   Name: myJson[key].Name
 };

 if(item.Id != "01" || item.Id !="02")
 {
   alert(item.Id);   
 }
}

I am expecting to just show an alert as "03" but it shows 3 alert each for "01", "02" & "03"

Looks like != and OR operator not working ?

Answer 1

The || operator only returns false when both of its operands are false (and true in all other cases).

The && operator only returns true when both of its operands are true (and false in all other cases).

You have to use && instead of || in the if condition to get the expected result:

var data = "[{\"Id\":\"01\",\"Name\":\"01- Alabama\"},{\"Id\":\"02\",\"Name\":\"02- Arizona\"},{\"Id\":\"03\",\"Name\":\"03- Arkansas\"}]";

 var myJson = JSON.parse(data);
 for (var key in myJson) {
   var item = {
   Id: myJson[key].Id,
   Name: myJson[key].Name
 };

 if(item.Id != "01" && item.Id !="02")
 {
   alert(item.Id);   
 }
}

Answer 2

Actually is working as expected because the OR operator is returning true for cases when Id == 01 and Id == 02

What you want to do is to join the two operands with AND operator && and this way execute the logic just when Id != 01 AND Id != 02.

var data = "[{\"Id\":\"01\",\"Name\":\"01- Alabama\"},{\"Id\":\"02\",\"Name\":\"02- Arizona\"},{\"Id\":\"03\",\"Name\":\"03- Arkansas\"}]";

var myJson = JSON.parse(data);
for (var key in myJson) {
  var item = {
    Id: myJson[key].Id,
    Name: myJson[key].Name
  };

  if (item.Id != "01" && item.Id != "02") {
    alert(item.Id);
  }
}