rspec/rules/S2769/javascript/rule.adoc

== Why is this an issue?

Once you've made a selection, you typically want to know whether it actually found anything. Since selectors _always_ return an object (the set of selected DOM elements), the best way to see whether your selection found anything is to test the returned object's ``++.length++`` property. 


=== Noncompliant code example

[source,javascript]
----
if ( $( "div.foo" ) ) {  // Noncompliant
  // this code always runs, even when the selector didn't match any elements
  // ...
}
----


=== Compliant solution

[source,javascript]
----
// Testing whether a selection contains elements.
if ( $( "div.foo" ).length > 0) {
  // this code only runs if elements were found
  //  ...
}
----


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

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

=== Message

Use the "length" property to see whether this selection contains elements.


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

=== on 26 Mar 2015, 17:11:46 Linda Martin wrote:
\[~ann.campbell.2] Assigned for review and completion. The description is a copy/paste of \https://learn.jquery.com/using-jquery-core/selecting-elements/, I was afraid that if I started to rephrase it would not make any sens anymore.

=== on 27 Mar 2015, 15:24:13 Ann Campbell wrote:
double-check me, please [~linda.martin]

=== on 19 May 2015, 15:54:00 Linda Martin wrote:
Reviewed.

=== on 24 Apr 2017, 10:24:45 Elena Vilchik wrote:
\[~ann.campbell.2] why minor?

=== on 1 Nov 2019, 17:29:53 Elena Vilchik wrote:
See \https://github.com/SonarSource/SonarJS/issues/1698

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