== Why is this an issue?

include::../description.adoc[]

=== Noncompliant code example

[source,javascript]
----
function doSomething(a, b) { // "a" is unused
  return compute(b);
}
----

=== Compliant solution

[source,javascript]
----
function doSomething(b) {
  return compute(b);
}
----

or

[source,javascript]
----
function doSomething(_a, b) {
  return compute(b);
}
----



=== Exceptions

When ``++arguments++`` is used in the function body, no parameter is reported as unused.


[source,javascript]
----
function doSomething(a, b, c) {
  compute(arguments);
}
----

Also, the rule ignores all parameters whose name starts with an underscore (``++_++``). 
This is a common practice to acknowledge the fact that some parameter is unused (e.g. in TypeScript compiler).

[source,javascript]
----
function doSomething(_a, b) {
  return compute(b);
}
----


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

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

include::../message.adoc[]

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

=== on 9 Apr 2015, 11:15:56 Elena Vilchik wrote:
I removed part "for function-expression" from Exceptions block, as there is no difference between usage of function-declarations and function-expressions. In some cases (passing functions as arguments to other functions) function-expressions are more common, but function-declarations are still in use.

include::../comments-and-links.adoc[]

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