rspec/rules/S935/javascript/rule.adoc

== Why is this an issue?

Every call to a function with a non-void return type is expected to return some value. If there is no value that's valid, you should ``++return undefined;++`` rather than using a void return (``++return;++``).  Conversely, every call to a function with a void return type is expected to not return any value, even ``++undefined++``. 


This rule raises an issue when ``++undefined++`` is returned from a void function, and when void is returned from a non-void function.

=== Noncompliant code example

[source,javascript]
----
function nonvoidFunction(): number | undefined {
    return;  // Noncompliant
}

function voidFunction(): void {
    return undefined;  // Noncompliant
}
----

=== Compliant solution

[source,javascript]
----
function nonvoidFunction(): number | undefined {
    return undefined;
}

function voidFunction(): void {
    return;
}
----

== Resources

* CWE - https://cwe.mitre.org/data/definitions/394[CWE-394 - Unexpected Status Code or Return Value]


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

include::../message.adoc[]

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

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