rspec/rules/S4173/swift/rule.adoc

== Why is this an issue?

If you only want one instance that matches certain criteria out of a collection, it's far more efficient to grab the first matching item than it is to fully filter the collection for your criteria and then only use a single value.


=== Noncompliant code example

[source,swift]
----
let one = arr.filter { $0.containsString("yo") }.first  // Noncompliant
----


=== Compliant solution

[source,swift]
----
let one = arr.first(where: { $0.containsString("yo") })
----

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

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

=== Message

Convert this "filter...first" operation to "first(where: ...)".


=== Highlighting

primary: ``++first++``

secondary: ``++filter++``


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