Add function to make elements in an array unique

Sources/AppFoundations/Extensions/Array/Array+Modifying.swift

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+//
+//  File.swift
+//  
+//
+//  Created by Mark DiFranco on 2023-09-04.
+//
+
+import Foundation
+
+public extension Array {
+
+    /// Returns a new array with the provided `element` inserted.
+    /// - parameter element: The element to insert.
+    /// - returns: A new array with the provided `element` inserted.
+    func inserting(_ element: Element) -> Self {
+        self + [element]
+    }
+}

Sources/AppFoundations/Extensions/Array/Array+Unique.swift

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+//
+//  Array+Unique.swift
+//  
+//
+//  Created by Mark DiFranco on 2023-09-04.
+//
+
+import Foundation
+
+public extension Array where Element: Equatable {
+
+    mutating func madeUnique() {
+        self = makingUnique()
+    }
+
+    func makingUnique() -> Self {
+        reduce([]) { (partialResult, element) in
+            if partialResult.contains(element) {
+                return partialResult
+            }
+            return partialResult.inserting(element)
+        }
+    }
+}

Tests/AppFoundationsTests/Extensions/Array/Array+Unique.swift

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+//
+//  Array+Unique.swift
+//  
+//
+//  Created by Mark DiFranco on 2023-09-04.
+//
+
+import XCTest
+
+final class Array_Unique: XCTestCase {
+
+    var sut = [String]()
+
+    func test_madeUnique_returnsUniqueElements() {
+        // Arrange
+        sut = ["One", "One", "Two", "One", "Three"]
+        let expectedResult = ["One", "Two", "Three"]
+
+        // Act
+        sut.madeUnique()
+
+        // Assert
+        XCTAssertEqual(sut, expectedResult)
+    }
+
+    func test_makingUnique_returnsUniqueElements() {
+        // Arrange
+        sut = ["One", "One", "Two", "One", "Three"]
+        let expectedResult = ["One", "Two", "Three"]
+
+        // Act
+        let result = sut.makingUnique()
+
+        // Assert
+        XCTAssertEqual(result, expectedResult)
+    }
+
+    func test_makingUnique_performance() {
+        // Arrange
+        sut = Array(repeating: "Hello World", count: 100_000)
+        let expectedResult = ["Hello World"]
+
+        // Act
+        self.measure {
+            let result = sut.makingUnique()
+
+            // Assert
+            XCTAssertEqual(result, expectedResult)
+        }
+    }
+}