How to manage Date Object without third libraries [Swift] 📆

Introduction

Recently I worked on an iOS app and I had to handle some Date object in my project. I made some research about it and I found a lot of third libraries which handle the management of Date/Time object. With them, we are able to handle some picker, format them to display it to the user, and play with the data and the format.

I didn’t know which one to use and I didn’t really wanted to use one. Handle Date object is not too complicated to do by yourself so I preferred doing it better than adding another third libraries. In general I try to use less third libraries as possible for performance, dependencies and app size purpose.

So let’s dive in !

One file : DateTimeUtils.swift

I will use only one file that will be accessible everywhere within my app. Usually I use a folder Utils for that type of file. So let’s create that file like this :

//
//  DateTimeUtils.swift
//
//  Copyright © 2017 Borombo. All rights reserved.
//

import Foundation

class DateTimeUtils {
    
    // Unique instance (Singleton)
    static let instance = DateTimeUtils()

}

// DateTimeUtils.swift

import Foundation

class DateTimeUtils {

// Unique instance (Singleton)

static let instance = DateTimeUtils()

}

After that, I will set the Locale and the saved format. The application that I made was made only for French people so I only used the French locale, but you can set the one that you want . The saved format is the format that I will save the date for my database.

    // Select the locale
    static let LOCALE = "FR-fr"
    static let SAVED_FORMAT = "yyyy-MM-dd'T'HH:mm:ssZ"

// Select the locale

static let LOCALE = "FR-fr"

static let SAVED_FORMAT = "yyyy-MM-dd'T'HH:mm:ssZ"

Then, I will set different formatter. I will use them for… formate my Date object. Actually I need four of them, one for display it in the app, two for only take the date or the hour, and the last one for the saved format on database. Obviously, you do it for the format that you need.

    // Different formatter
    private let french = DateFormatter()
    private let dateOnly = DateFormatter()
    private let hourOnly = DateFormatter()
    private let savedFormat = DateFormatter()

// Different formatter

private let french = DateFormatter()

private let dateOnly = DateFormatter()

private let hourOnly = DateFormatter()

private let savedFormat = DateFormatter()

Initialization

I will need an init function to initialize the format of all my formatters. Depending of your needs, you setup your formatter like you want.

    init() {
        french.dateStyle = .long
        french.timeStyle = .short
        
        dateOnly.dateStyle = .long
        dateOnly.timeStyle = .none

        hourOnly.dateStyle = .none
        hourOnly.timeStyle = .short
        
        french.locale    = Locale(identifier: DateTimeUtils.LOCALE)
        dateOnly.locale    = Locale(identifier: DateTimeUtils.LOCALE)
        hourOnly.locale    = Locale(identifier: DateTimeUtils.LOCALE)
        
        savedFormat.dateFormat = DateTimeUtils.SAVED_FORMAT
    }

init() {

french.dateStyle = .long

french.timeStyle = .short

dateOnly.dateStyle = .long

dateOnly.timeStyle = .none

hourOnly.dateStyle = .none

hourOnly.timeStyle = .short

french.locale = Locale(identifier: DateTimeUtils.LOCALE)

dateOnly.locale = Locale(identifier: DateTimeUtils.LOCALE)

hourOnly.locale = Locale(identifier: DateTimeUtils.LOCALE)

savedFormat.dateFormat = DateTimeUtils.SAVED_FORMAT

}

Functions

The final part is to create all the functions that I will need within my app :

The first one for example is to get the Date object from the formatted String saved in my database

    func getDateFromSaved(saved: String)-> Date{
        return savedFormat.date(from: saved)!
    }

func getDateFromSaved(saved: String)-> Date{

return savedFormat.date(from: saved)!

}

Obviously I also need the reverse action

    // Transform a Date object to the saved format
    func dateToSavedFormat(date: Date) -> String {
        return savedFormat.string(from: date)
    }

// Transform a Date object to the saved format

func dateToSavedFormat(date: Date) -> String {

return savedFormat.string(from: date)

}

I needed few others functions for my app, but they all works in the same way. You can make the one that you will need in your app.

    // Transform a Date object to a Full Date-Time String
    func dateToFrench(date: Date) -> String{
        var stringDate = french.string(from: date)
        stringDate = stringDate.capitalized 
        return stringDate.replacingOccurrences(of: "À", with: "à")
    }

    // Get the String full date-time from the string saved format
    func savedToFrench(savedDate: String) -> String {
        return french.string(from: (savedFormat.date(from: savedDate))!)
    }
    
    // Get only the date from the string saved format
    func getDateFromSaved(savedDate: String) -> String {
        return dateOnly.string(from: (savedFormat.date(from: savedDate))!)
    }
    
    // Get only the hour from the string saved format
    func getHourFromSaved(savedDate: String) -> String {
        return hourOnly.string(from: (savedFormat.date(from: savedDate))!)
    }

// Transform a Date object to a Full Date-Time String

func dateToFrench(date: Date) -> String{

var stringDate = french.string(from: date)

stringDate = stringDate.capitalized

return stringDate.replacingOccurrences(of: "À", with: "à")

}

// Get the String full date-time from the string saved format

func savedToFrench(savedDate: String) -> String {

return french.string(from: (savedFormat.date(from: savedDate))!)

}

// Get only the date from the string saved format

func getDateFromSaved(savedDate: String) -> String {

return dateOnly.string(from: (savedFormat.date(from: savedDate))!)

}

// Get only the hour from the string saved format

func getHourFromSaved(savedDate: String) -> String {

return hourOnly.string(from: (savedFormat.date(from: savedDate))!)

}

Utilization

Here is one of the use that I do with

playerData["birthDate"] = DateTimeUtils.instance.dateToSavedFormat(date: selectedDate)

// OR 

birthDateLabel.text = DateTimeUtils.instance.getDateFromSaved(savedDate: (player?.birthDate)!)

playerData["birthDate"] = DateTimeUtils.instance.dateToSavedFormat(date: selectedDate)

// OR

birthDateLabel.text = DateTimeUtils.instance.getDateFromSaved(savedDate: (player?.birthDate)!)

As all your variable are declared at the beginning, you can easily change the format or the local of your app without to have to write all the functions again.

Here it’s how looks the final file :

//
//  DateTimeUtils.swift
//
// Created by Erwan Rombo on 19/10/2017.
//  Copyright © 2017 Borombo. All rights reserved.
//

import Foundation

class DateTimeUtils {
    
    // Unique instance (Singleton)
    static let instance = DateTimeUtils()
    
    // Select the locale
    static let LOCALE = "FR-fr"
    static let SAVED_FORMAT = "yyyy-MM-dd'T'HH:mm:ssZ"
    
    // Different formatter
    private let french = DateFormatter()
    private let dateOnly = DateFormatter()
    private let hourOnly = DateFormatter()
    private let savedFormat = DateFormatter()
    
    init() {
        french.dateStyle = .long
        french.timeStyle = .short
        
        dateOnly.dateStyle = .long
        dateOnly.timeStyle = .none

        hourOnly.dateStyle = .none
        hourOnly.timeStyle = .short
        
        french.locale    = Locale(identifier: DateTimeUtils.LOCALE)
        dateOnly.locale    = Locale(identifier: DateTimeUtils.LOCALE)
        hourOnly.locale    = Locale(identifier: DateTimeUtils.LOCALE)
        
        savedFormat.dateFormat = DateTimeUtils.SAVED_FORMAT
    }
    
    func getDateFromSaved(saved: String)-> Date{
        return savedFormat.date(from: saved)!
    }
    
    // Transform a Date object to a Full Date-Time String
    func dateToFrench(date: Date) -> String{
        var stringDate = french.string(from: date)
        stringDate = stringDate.capitalized
        let res = stringDate.replacingOccurrences(of: "À", with: "à")
        return res
    }
    
    // Transform a Date object to the saved format
    func dateToSavedFormat(date: Date) -> String {
        return savedFormat.string(from: date)
    }
    
    // Get the String full date-time from the string saved format
    func savedToFrench(savedDate: String) -> String {
        return french.string(from: (savedFormat.date(from: savedDate))!)
    }
    
    // Get only the date from the string saved format
    func getDateFromSaved(savedDate: String) -> String {
        return dateOnly.string(from: (savedFormat.date(from: savedDate))!)
    }
    
    // Get only the hour from the string saved format
    func getHourFromSaved(savedDate: String) -> String {
        return hourOnly.string(from: (savedFormat.date(from: savedDate))!)
    }
    
}