Simplify date formatters

Author: kean

NaiveDate.playground/Contents.swift

@@ -11,7 +11,7 @@ import NaiveDate
 let date = NaiveDate("2017-11-01")!
 Calendar.current.date(from: date)
 
-NaiveDateFormatter(dateStyle: .short).string(from: date)
+NaiveDateFormatter(dateStyle: .medium).string(from: date)
 
 
 /*:
@@ -34,4 +34,4 @@ NaiveDateFormatter(timeStyle: .short).string(from: time)
 let dateTime = NaiveDateTime("2017-11-01T15:30:00")!
 Calendar.current.date(from: dateTime)
 
-NaiveDateFormatter(dateStyle: .short, timeStyle: .short).string(from: dateTime)
+NaiveDateFormatter(dateStyle: .medium, timeStyle: .short).string(from: dateTime)

README.md

@@ -48,15 +48,15 @@ Format dates without having to worry about time zones:
 ```swift
 let date = NaiveDate("2017-11-01")!
 NaiveDateFormatter(dateStyle: .short).string(from: date)
-// prints "11/1/17"
+// prints "Nov 1, 2017"
 
 let time = NaiveTime("15:00")!
 NaiveDateFormatter(timeStyle: .short).string(from: time)
 // prints "3:00 PM"
 
 let dateTime = NaiveDateTime("2017-11-01T15:30:00")!
 NaiveDateFormatter(dateStyle: .short, timeStyle: .short).string(from: dateTime)
-// prints "11/1/17, 3:30 PM"
+// prints "Nov 1, 2017 at 3:30 PM"
 ```
 
 ### Convert

Sources/NaiveDateFormatter.swift

@@ -9,32 +9,36 @@ import Foundation
 
 /// Formatting without time zones.
 public final class NaiveDateFormatter {
-    private var formatter = DateFormatter()
-    private let converter = NaiveDateTimeConverter()
+    private let formatter = DateFormatter()
 
-    public init(locale: Locale = Locale.current, format: String) {
-        formatter.locale = locale
-        formatter.timeZone = converter.timeZone // important! UTC to UTC
-        formatter.dateFormat = format
+    public init(_ closure: (_ formatter: DateFormatter) -> Void) {
+        closure(formatter)
+        self.formatter.timeZone = TimeZone._utc // important! UTC to UTC
     }
 
-    public init(locale: Locale = Locale.current, dateStyle: DateFormatter.Style = .none, timeStyle: DateFormatter.Style = .none) {
-        formatter.locale = locale
-        formatter.timeZone = converter.timeZone // important! UTC to UTC
-        formatter.dateStyle = dateStyle
-        formatter.timeStyle = timeStyle
+    public convenience init(format: String) {
+        self.init {
+            $0.dateFormat = format
+        }
     }
 
-    public func string(from date: NaiveDate) -> String? {
-        return converter.date(from: date).map { formatter.string(from: $0) }
+    public convenience init(dateStyle: DateFormatter.Style = .none, timeStyle: DateFormatter.Style = .none) {
+        self.init {
+            $0.dateStyle = dateStyle
+            $0.timeStyle = timeStyle
+        }
     }
 
-    public func string(from time: NaiveTime) -> String? {
-        return converter.date(from: time).map { formatter.string(from: $0) }
+    public func string(from value: NaiveDate) -> String? {
+        return formatter.calendar._utcDate(from: value).map { formatter.string(from: $0) }
     }
 
-    public func string(from dateTime: NaiveDateTime) -> String? {
-        return converter.date(from: dateTime).map { formatter.string(from: $0) }
+    public func string(from value: NaiveTime) -> String? {
+        return formatter.calendar._utcDate(from: value).map { formatter.string(from: $0) }
+    }
+
+    public func string(from value: NaiveDateTime) -> String? {
+        return formatter.calendar._utcDate(from: value).map { formatter.string(from: $0) }
     }
 }
 
@@ -44,48 +48,52 @@ public final class NaiveDateFormatter {
 /// Formatting without time zones.
 public final class NaiveDateRangeFormatter {
     private let formatter = DateIntervalFormatter()
-    private let converter = NaiveDateTimeConverter()
 
-    public init(locale: Locale = Locale.current, format: String) {
-        formatter.locale = locale
-        formatter.timeZone = converter.timeZone // important! UTC to UTC
-        formatter.dateTemplate = format
+    public init(_ closure: (_ formatter: DateIntervalFormatter) -> Void) {
+        closure(formatter)
+        self.formatter.timeZone = TimeZone._utc // important! UTC to UTC
     }
 
-    public init(locale: Locale = Locale.current, dateStyle: DateIntervalFormatter.Style = .none, timeStyle: DateIntervalFormatter.Style = .none) {
-        formatter.locale = locale
-        formatter.timeZone = converter.timeZone // important! UTC to UTC
-        formatter.dateStyle = dateStyle
-        formatter.timeStyle = timeStyle
+    public convenience init(format: String) {
+        self.init {
+            $0.dateTemplate = format
+        }
+    }
+
+    public convenience init(dateStyle: DateIntervalFormatter.Style = .none, timeStyle: DateIntervalFormatter.Style = .none) {
+        self.init {
+            $0.dateStyle = dateStyle
+            $0.timeStyle = timeStyle
+        }
     }
 
     public func string(from start: NaiveDate, to end: NaiveDate) -> String? {
-        return converter.dateRange(from: start, to: end).map { formatter.string(from: $0, to: $1) }
+        return formatter.calendar._utcDateRange(from: start, to: end).map { formatter.string(from: $0, to: $1) }
     }
 
     public func string(from start: NaiveTime, to end: NaiveTime) -> String? {
-        return converter.dateRange(from: start, to: end).map { formatter.string(from: $0, to: $1) }
+        return formatter.calendar._utcDateRange(from: start, to: end).map { formatter.string(from: $0, to: $1) }
     }
 
     public func string(from start: NaiveDateTime, to end: NaiveDateTime) -> String? {
-        return converter.dateRange(from: start, to: end).map { formatter.string(from: $0, to: $1) }
+        return formatter.calendar._utcDateRange(from: start, to: end).map { formatter.string(from: $0, to: $1) }
     }
 }
 
 
 // MARK: - Private -
 
-/// Converts `Naive*` to `Date` in UTC.
-private final class NaiveDateTimeConverter {
-    private let calendar = Calendar.current
-    let timeZone = TimeZone(secondsFromGMT: 0)!
+private extension TimeZone {
+    static let _utc = TimeZone(secondsFromGMT: 0)!
+}
 
-    func date<T: _DateComponentsConvertible>(from date: T) -> Date? {
-        return calendar._date(from: date, in: timeZone)
+private extension Calendar {
+    func _utcDate<T: _DateComponentsConvertible>(from date: T) -> Date? {
+        return self._date(from: date, in: TimeZone._utc)
     }
 
-    func dateRange<T: _DateComponentsConvertible>(from start: T, to end: T) -> (Date, Date)? {
-        guard let start = date(from: start), let end = date(from: end) else { return nil }
+    func _utcDateRange<T: _DateComponentsConvertible>(from start: T, to end: T) -> (Date, Date)? {
+        guard let start = _date(from: start), let end = _date(from: end) else { return nil }
         return (start, end)
     }
 }

Tests/NaiveDateFormatterTest.swift

@@ -8,14 +8,20 @@ import NaiveDate
 
 class NaiveDateFormatterTest: XCTestCase {
     func testNaiveTimeFormatter_enUS() {
-        let formatter = NaiveDateFormatter(locale: Locale(identifier: "en_US"), dateStyle: .none, timeStyle: .short)
+        let formatter = NaiveDateFormatter {
+            $0.locale = Locale(identifier: "en_US")
+            $0.timeStyle = .short
+        }
 
         XCTAssertEqual(formatter.string(from: NaiveTime("16:10")!), "4:10 PM")
         XCTAssertEqual(formatter.string(from: NaiveTime("16:10:15")!), "4:10 PM")
     }
 
     func testNaiveTimeFormatter_enGB() {
-        let formatter = NaiveDateFormatter(locale: Locale(identifier: "en_GB"), dateStyle: .none, timeStyle: .short)
+        let formatter = NaiveDateFormatter {
+            $0.locale = Locale(identifier: "en_GB")
+            $0.timeStyle = .short
+        }
 
         XCTAssertEqual(formatter.string(from: NaiveTime("16:10")!), "16:10")
         XCTAssertEqual(formatter.string(from: NaiveTime("16:10:15")!), "16:10")