rspec/rules/S3758/javascript/rule.adoc

In a Zen-like manner, ``++NaN++`` isn't equal to anything, even itself. So comparisons (``++>, <, >=, <=++``) where one operand is ``++NaN++`` or evaluates to ``++NaN++`` always return ``++false++``. Specifically, ``++undefined++`` and objects that cannot be converted to numbers evaluate to ``++NaN++`` when used in numerical comparisons.


This rule raises an issue when there is at least one path through the code where one of the operands to a comparison is ``++NaN++``, ``++undefined++`` or an ``++Object++`` which cannot be converted to a number.


== Noncompliant Code Example

----
var x;  // x is currently "undefined"
if (someCondition()) {
  x = 42;  
}

if (42 > x) {  // Noncompliant; "x" might still be "undefined"
  doSomething();
}

var obj = {prop: 42};
if (obj > 24) { // Noncompliant 
  doSomething();
}
----


== Compliant Solution

----
var x;
if (someCondition()) {
  x = 42;
} else {
  x = foo();
}

if (42 > x) {
  doSomething();
}

var obj = {prop: 42};
if (obj.prop > 24) {
  doSomething();
}
----


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== Comments And Links
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include::comments-and-links.adoc[]
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