Add rule to prefer count(where: { ... }) over filter { ... }.count

airbnb · Dec 9, 2024 · f60fa7d · f60fa7d
1 parent 25cc395
commit f60fa7d
Show file tree

Hide file tree

Showing 2 changed files with 16 additions and 0 deletions.
diff --git a/README.md b/README.md
@@ -3802,6 +3802,21 @@ _You can enable the following settings in Xcode by running [this script](resourc
   ```
   </details>
 
+* <a id='count-where'></a>(<a href='#count-where'>link</a>) **Prefer `count(where: { … })` over `filter { … }.count`**.
+
+  <details>
+
+  Swift 6.0 ([finally!](https://forums.swift.org/t/accepted-again-se-0220-count-where/66659)) added a `count(where:)` method to the standard library. Prefer using the `count(where:)` method over using the `filter(_:)` method followed by a `count` call.
+
+  ```swift
+  // WRONG
+  let planetsWithMoons = planets.filter { !$0.moons.isEmpty }.count
+
+  // RIGHT
+  let planetsWithMoons = planets.count(where: { !$0.moons.isEmpty })
+  ```
+  </details>
+
 **[⬆ back to top](#table-of-contents)**
 
 ## File Organization

diff --git a/Sources/AirbnbSwiftFormatTool/airbnb.swiftformat b/Sources/AirbnbSwiftFormatTool/airbnb.swiftformat
@@ -121,3 +121,4 @@
 --rules blankLinesBetweenChainedFunctions
 --rules unusedPrivateDeclaration
 --rules emptyExtension
+--rules preferCountWhere