rspec/rules/S2684/javascript/rule.adoc

== Why is this an issue?

``++null++`` and ``++undefined++`` are similar but not synonymous concepts in Javascript. Use a "hard" test (``++===++`` or ``++!==++``) for one, and you'll miss the other. Soft tests (``++==++``, and ``++!=++``) on the other hand, will pick up both non-values, as well as empty string.


Even if you mean to make the distinction in your code between ``++null++`` and ``++undefined++``, doing so is an extremely questionable practice that is likely to confuse both users and maintainers. Instead, use one or the other and test for both using soft tests.


=== Noncompliant code example

[source,javascript]
----
function func1(p1, p2) {

  if (p1 === null) {  // Noncompliant 
    return;
  }
  if (p1 === undefined) { // Noncompliant
    return;
  }
  // ...
}
----


=== Compliant solution

[source,javascript]
----
function func1(p1, p2) {

  if (p1 == null) {  // true for null, undefined
    return;
  }
  // ...
}
----


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

=== Message

Use the "xx" operator instead.


'''
== Comments And Links
(visible only on this page)

=== on 13 Nov 2015, 14:58:00 Linda Martin wrote:
\[~elena.vilchik] I think this rule requires some digging, I let you do that.

endif::env-github,rspecator-view[]