Make RelativeDateFormatter locale/timeZone aware

Packages/Formatters/Sources/RelativeDateFormatter.swift

@@ -3,42 +3,51 @@
 import Foundation
 
 public struct RelativeDateFormatter: Sendable {
-    private static let relativeFormatter: DateFormatter = {
-        let formatter = DateFormatter()
-        formatter.timeStyle = .none
-        formatter.dateStyle = .medium
-        formatter.doesRelativeDateFormatting = true
-        return formatter
-    }()
+    let relativeFormatter: DateFormatter
+    let time: DateFormatter
+    let dateAndTime: DateFormatter
+    let calendar: Calendar
 
-    private static let time: DateFormatter = {
-        let formatter = DateFormatter()
-        formatter.timeStyle = .short
-        formatter.dateStyle = .none
-        return formatter
-    }()
+    public init(locale: Locale = .current, timeZone: TimeZone = .current) {
+        var calendar = Calendar.current
+        calendar.locale = locale
+        calendar.timeZone = timeZone
+        self.calendar = calendar
 
-    private static let dateAndTime: DateFormatter = {
-        let formatter = DateFormatter()
-        formatter.timeStyle = .short
-        formatter.dateStyle = .long
-        return formatter
-    }()
+        relativeFormatter = {
+            let formatter = DateFormatter()
+            formatter.timeStyle = .none
+            formatter.dateStyle = .medium
+            formatter.doesRelativeDateFormatting = true
+            formatter.locale = locale
+            formatter.timeZone = timeZone
+            return formatter
+        }()
 
-    private static let dateOnly: DateFormatter = {
-        let formatter = DateFormatter()
-        formatter.timeStyle = .none
-        formatter.dateStyle = .long
-        return formatter
-    }()
+        time = {
+            let formatter = DateFormatter()
+            formatter.timeStyle = .short
+            formatter.dateStyle = .none
+            formatter.locale = locale
+            formatter.timeZone = timeZone
+            return formatter
+        }()
 
-    public init() {}
+        dateAndTime = {
+            let formatter = DateFormatter()
+            formatter.timeStyle = .short
+            formatter.dateStyle = .long
+            formatter.locale = locale
+            formatter.timeZone = timeZone
+            return formatter
+        }()
+    }
 
     public func string(from date: Date) -> String {
-        if Calendar.current.isDateInToday(date) || Calendar.current.isDateInYesterday(date) {
-            let relativeDate = Self.relativeFormatter.string(from: date)
-            return String(format: "%@, %@", relativeDate, Self.time.string(from: date))
+        if calendar.isDateInToday(date) || calendar.isDateInYesterday(date) {
+            let relativeDate = relativeFormatter.string(from: date)
+            return String(format: "%@, %@", relativeDate, time.string(from: date))
         }
-        return Self.dateAndTime.string(from: date)
+        return dateAndTime.string(from: date)
     }
 }

Packages/Formatters/Tests/FormattersTests/RelativeDateFormatterTests.swift

@@ -1,38 +1,45 @@
 // Copyright (c). Gem Wallet. All rights reserved.
 
-import Testing
-import Foundation
 @testable import Formatters
+import Foundation
+import Testing
 
 struct RelativeDateFormatterTests {
-    private let formatter = RelativeDateFormatter()
+    private let locale = Locale.US
+    private let timeZone = TimeZone.NewYork!
+    private let formatter: RelativeDateFormatter
+    private let calendar: Calendar
+
+    init() {
+        formatter = RelativeDateFormatter(locale: locale, timeZone: timeZone)
+        calendar = formatter.calendar
+    }
 
     @Test
-    func today() {
-        let calendar = Calendar.current
-        let todayWithTime = calendar.date(bySettingHour: 14, minute: 30, second: 0, of: Date())!
+    func today() throws {
+        let todayWithTime = try #require(calendar.date(bySettingHour: 14, minute: 30, second: 0, of: Date()))
 
         #expect(formatter.string(from: todayWithTime) == "Today, 2:30 PM")
     }
 
     @Test
-    func yesterday() {
-        let calendar = Calendar.current
-        let yesterdayDate = calendar.date(byAdding: .day, value: -1, to: Date())!
+    func yesterday() throws {
+        let yesterdayDate = try #require(calendar.date(byAdding: .day, value: -1, to: Date()))
+        let yesterdayWithTime = try #require(calendar.date(bySettingHour: 9, minute: 15, second: 0, of: yesterdayDate))
 
-        let yesterdayWithTime = calendar.date(bySettingHour: 9, minute: 15, second: 0, of: yesterdayDate)!
         #expect(formatter.string(from: yesterdayWithTime) == "Yesterday, 9:15 AM")
     }
 
     @Test
-    func oneMonthOld() {
+    func oneMonthOld() throws {
         var components = DateComponents()
         components.year = 2025
         components.month = 2
         components.day = 2
         components.hour = 10
         components.minute = 25
-        let date = Calendar.current.date(from: components)!
+        components.timeZone = timeZone
+        let date = try #require(calendar.date(from: components))
 
         #expect(formatter.string(from: date) == "February 2, 2025 at 10:25 AM")
     }

Packages/Primitives/Sources/Extensions/Timezone+Primitives.swift

@@ -0,0 +1,6 @@
+
+import Foundation
+
+extension TimeZone {
+    public static let NewYork = TimeZone(identifier: "America/New_York")
+}