rspec/rules/S1526/javascript/rule.adoc

Variables declared with ``++var++`` have the special property that regardless of where they're declared in a function they "float" to the top of the function and are available for use even before they're declared. That makes scoping confusing, especially for new coders. 

To keep confusion to a minimum, ``++var++`` declarations should happen before they are used for the first time.

== Noncompliant Code Example

----
var x = 1;

function fun(){
  alert(x); // Noncompliant as x is declared later in the same scope
  if(something) {
    var x = 42; // Declaration in function scope (not block scope!) shadows global variable
  }
}

fun(); // Unexpectedly alerts "undefined" instead of "1"
----


== Compliant Solution

----
var x = 1;

function fun() {
  print(x);
  if (something) {
    x = 42;
  }
}

fun(); // Print "1"
----