[dart] How do I format a date with Dart?

I have an instance of DateTime and I would like to format that to a String. How do I do that? I want to turn the date into a string, something like "2013-04-20".

pubspec.yaml:

dependencies:
  intl:

main.dart:

import 'package:intl/intl.dart'; // for date format
import 'package:intl/date_symbol_data_local.dart'; // for other locales

void main() {
  var now = DateTime.now();
  print(DateFormat().format(now)); // This will return date using the default locale
  print(DateFormat('yyyy-MM-dd hh:mm:ss').format(now));
  print(DateFormat.yMMMMd().format(now)); // print long date 
  print(DateFormat.yMd().format(now)); // print short date 
  print(DateFormat.jms().format(now)); // print time 

  initializeDateFormatting('es'); // This will initialize Spanish locale
  print(DateFormat.yMMMMd('es').format(now)); // print long date in Spanish format
  print(DateFormat.yMd('es').format(now)); // print short date in Spanish format
  print(DateFormat.jms('es').format(now)); // print time in Spanish format
}

Result:

May 31, 2020 5:41:42 PM
2020-05-31 05:41:42
May 31, 2020
5/31/2020
5:41:42 PM
31 de mayo de 2020
31/5/2020
17:41:42

String formatDate(String date) {
    return date.substring(0, 10).split('-').reversed.join().replaceAll('-', '/');
    
  }

From format "yyyy-mm-dd H:i:s"

You can use this method as well, if you don't want to add another library

  DateTime dateTime = DateTime.now();
  String YYYY_MM_DD = dateTime.toIso8601String().split('T').first;
  print(YYYY_MM_DD); //2020-11-23

There is a package date_format

dependencies:
    date_format:

code

import 'package:date_format/date_format.dart';

final formattedStr = formatDate(
    yourDateTime, [dd, '.', mm, '.', yy, ' ', HH, ':', nn]);

// output example "29.03.19 07:00"

Pay attention: minutes are nn

link to the package

This will work too:

DateTime today = new DateTime.now();
String dateSlug ="${today.year.toString()}-${today.month.toString().padLeft(2,'0')}-${today.day.toString().padLeft(2,'0')}";
print(dateSlug);

import 'package:intl/intl.dart';

main() {
  var formattedDate = new DateTime.Format('yyyy-MM-dd').DateTime.now();
  print(formattedDate); // something like 2020-04-16
}

For more details can refer DateFormat Documentation

You can also specify the date format like stated earlier: https://pub.dev/documentation/intl/latest/intl/DateFormat-class.html

import 'package:intl/intl.dart';
String formatDate(DateTime date) => new DateFormat("MMMM d").format(date);

Produces: March 4

 String dateConverter(String date) {
    // Input date Format
    final format = DateFormat("dd-MM-yyyy");
    DateTime gettingDate = format.parse(date);
    final DateFormat formatter = DateFormat('yyyy-MM-dd');
    // Output Date Format
    final String formatted = formatter.format(gettingDate);
    return date;
  }

If someone wants to convert a date in string format to some other string format first use DateTime.parse("2019-09-30") then pass it to DateFormat("date pattern").format() like

dateFormate = DateFormat("dd-MM-yyyy").format(DateTime.parse("2019-09-30"));

Reference: Dart - How to change format of simple date string which is in yyyy-MM-dd to dd-MM-yyyy

handling yearly quarters, from string to DateTime, I didn't find proper solution so made this:

    List<String> dateAsList = 'Q1 2001'.split(' ');
    DateTime dateTime = DateTime.now();
    String quarter = dateAsList[0];
    int year = int.parse(dateAsList[1]);
    switch(quarter) {
      case "Q1": dateTime = DateTime(year, 1);
      break;
      case "Q2": dateTime = DateTime(year, 4);
      break;
      case "Q3": dateTime = DateTime(year, 7);
      break;
      case "Q4": dateTime = DateTime(year, 10);
      break;
    }

This give you the date like in a social network : ["today","yesterday","dayoftheweek",etc..]

void main() {
      DateTime now = new DateTime(2018,6,26);
      print(date(now));
    }
    
    String date(DateTime tm) {
      DateTime today = new DateTime.now();
      Duration oneDay = new Duration(days: 1);
      Duration twoDay = new Duration(days: 2);
      Duration oneWeek = new Duration(days: 7);
      String month;
      switch (tm.month) {
        case 1:
          month = "january";
          break;
        case 2:
          month = "february";
          break;
        case 3:
          month = "march";
          break;
        case 4:
          month = "april";
          break;
        case 5:
          month = "may";
          break;
        case 6:
          month = "june";
          break;
        case 7:
          month = "july";
          break;
        case 8:
          month = "august";
          break;
        case 9:
          month = "september";
          break;
        case 10:
          month = "october";
          break;
        case 11:
          month = "november";
          break;
        case 12:
          month = "december";
          break;
      }
    
      Duration difference = today.difference(tm);
    
      if (difference.compareTo(oneDay) < 1) {
        return "today";
      } else if (difference.compareTo(twoDay) < 1) {
        return "yesterday";
      } else if (difference.compareTo(oneWeek) < 1) {
        switch (tm.weekday) {
          case 1:
            return "monday";
          case 2:
            return "tuesday";
          case 3:
            return "wednesday";
          case 4:
            return "thursday";
          case 5:
            return "friday";
          case 6:
            return "saturday";
          case 7:
            return "sunday";
        }
      } else if (tm.year == today.year) {
        return '${tm.day} $month';
      } else {
        return '${tm.day} $month ${tm.year}';
      }
    }

In the case you want to combine several date format into one, this is how we can do using intl.

DateFormat('yMMMd').addPattern(DateFormat.HOUR24_MINUTE).format(yourDateTime))