feat: add the Scala-like contains functions to the Optional type

EmilioOjeda · Aug 8, 2023 · f6b20d2 · f6b20d2
1 parent f72ef0c
commit f6b20d2
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diff --git a/Sources/SwiftExtended/Optional.swift b/Sources/SwiftExtended/Optional.swift
@@ -99,3 +99,25 @@ public extension Optional {
             .flatMap(transform)
     }
 }
+
+public extension Optional where Wrapped: Equatable {
+    /// Checks if the value is wrapped within the `Optional` type.
+    /// - Parameter value: The value to search for.
+    /// - Returns: Whether the given value is wrapped in the `Optional` type.
+    func contains(_ value: Wrapped) -> Bool {
+        self == value
+    }
+}
+
+public extension Optional where Wrapped: Collection, Wrapped.Element: Equatable {
+    /// Checks if the value is present in the `Collection` wrapped within the `Optional` type.
+    /// - Parameter element: The value to search for.
+    /// - Returns: Whether the given value is present in the `Collection` wrapped in the `Optiona` type.
+    func contains(_ element: Wrapped.Element) -> Bool {
+        guard let collection = self else {
+            return false
+        }
+        return collection
+            .contains(where: \.self == element)
+    }
+}
diff --git a/Tests/SwiftExtendedTests/OptionalTests.swift b/Tests/SwiftExtendedTests/OptionalTests.swift
@@ -101,4 +101,45 @@ final class OptionalTests: XCTestCase {
                 .filter(where: \.self < numberTwo, then: String.init)
         )
     }
+
+    func testContains() {
+        // given
+        let letterA = "a"
+        let letterD = "d"
+        let lettersABC: [String] = ["a", "b", "c"]
+
+        // then
+        XCTAssertTrue(
+            Optional<String>
+                .some(letterA)
+                .contains(letterA)
+        )
+        XCTAssertFalse(
+            Optional<String>
+                .some(letterA)
+                .contains(letterD)
+        )
+        XCTAssertFalse(
+            Optional<String>
+                .none
+                .contains(letterA)
+        )
+
+        // also
+        XCTAssertTrue(
+            Optional<[String]>
+                .some(lettersABC)
+                .contains(letterA)
+        )
+        XCTAssertFalse(
+            Optional<[String]>
+                .some(lettersABC)
+                .contains(letterD)
+        )
+        XCTAssertFalse(
+            Optional<[String]>
+                .none
+                .contains(letterA)
+        )
+    }
 }