rspec/rules/S2692/javascript/rule.adoc

== Why is this an issue?

Most checks against an `indexOf` value compare it with -1 because 0 is a valid index. Checking against `> 0` ignores the first element, which is likely a bug.

[source,javascript]
----
var arr = ["blue", "red"];

if (arr.indexOf("blue") > 0) { // Noncompliant
  // ...
}
----

Moreover, if the intent is merely to check the presence of the element, and if your browser version supports it, consider using `includes` instead.

[source,javascript]
----
var arr = ["blue", "red"];

if (arr.includes("blue")) { 
  // ...
}
----

This rule raises an issue when an `indexOf` value retrieved from an array is tested against `> 0`.

== Resources

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes[Array.prototype.includes()] documentation at MDN

include::../rspecator.adoc[]