How to compare date string using javascript

Question

I have the following string value of a date, Sun Apr 07 2019 00:00:00 GMT-0300, and I need to compare with the following date format 2019-04-08T03:00:00.000Z, note that both are the same day, I need to compare them and return a true as being equal days,

but I do not know how to do this using javascript, any help?

I tried to do something like this but it does not return me true:

if (input) { 

     //input.value = "Sun Apr 07 2019 00:00:00 GMT-0300 (Horário Padrão de Brasília)"

     var situation = angular.isArray(item.situation) ? item.situation : [item.situation]; 

     // situation = 
     //[
     //    0: "2019-04-08T03:00:00.000Z"
     //    1: "2019-04-13T03:00:00.000Z"
     //]

     if (!angular.isArray(input.value)) {
        condition = situation.indexOf(input.value) >= 0;

     } else if (angular.isArray(input.value)) {
        condition = $window._.intersection(situation, input.value).length > 0;
     }
}

if (condition) {
    break;
}

//input.value = "Sun Apr 07 2019 00:00:00 GMT-0300 (Horário Padrão de Brasília)"

 situation = 
     [
         0: "2019-04-08T03:00:00.000Z"
         1: "2019-04-13T03:00:00.000Z"
     ]

What are your criteria for "same day"? Do you want the same UTC day, local day, or for a particular offset? — RobG
– RobG, Commented Apr 13, 2019 at 1:37

Styx · Accepted Answer · 2019-04-08 16:04:12Z

3

Sun Apr 07 2019 00:00:00 GMT-0300

2019-04-08T03:00:00.000Z

note that both are the same day

No, they are not.

You can convert them both to ISO string and just compare their date parts as strings (if I understood the question correctly, you want to compare date only, without time):

function isSameDate(date1, date2) {
  const [d1, ] = (new Date(date1)).toISOString().split('T');
  const [d2, ] = (new Date(date2)).toISOString().split('T');
  return d1 === d2;
}

answered Apr 8, 2019 at 16:04

Styx

10.1k8 gold badges48 silver badges56 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

RobG Over a year ago

Which could be: let isSameDate = (d0, d1) => new Date(d0).toDateString() == new Date(d1).toDateString();. :-) But only because the timestamps are supported by the ECMAScript 2018 or later. Implementations supporting previous versions may fail at parsing.

Styx Over a year ago

@RobG .toDateString() will convert date to your local timezone, whereas .toISOString() will convert to UTC. That could be the source of issues, that's why I choose the latter, but thanks for your input :)

RobG Over a year ago

My suggestion compares them as local, yours compares them as UTC. It doesn't matter, as long as they are both converted to the same offset for the comparison.

Styx Over a year ago

@RobG In most cases you'd be right, but as this code probably will be run on frontend it could produce different results for clients with different timezones.

RobG Over a year ago

Certainly, but the same issue occurs whether UTC or local is used as the epoch.

|

Davi · Accepted Answer · 2019-04-08 16:00:53Z

0

Convert all the values to Date objects and compare those. Use a framework/library to do it, because parsing strings to dates manually has lots of places where it can go wrong.

Currently you are comparing the literal Strings. Because neither "2019-04-08T03:00:00.000Z", nor "2019-04-13T03:00:00.000Z" match "Sun Apr 07 2019 00:00:00 GMT-0300 (Horário Padrão de Brasília)", your second if statement fails.

answered Apr 8, 2019 at 16:00

Davi

4,2941 gold badge18 silver badges29 bronze badges

Comments

Nino Filiu · Accepted Answer · 2019-04-08 16:00:16Z

-1

Build a date from the strings and compare the days (ie number of seconds since epoch / number of seconds in a day):

const sameDay = (dateString1, dateString2) => {
  let time1 = (new Date(dateString1)).getTime();
  let time2 = (new Date(dateString2)).getTime();
  return Math.floor(Math.abs((time1-time2))/(1000*60*60*24))==0;
}

console.log(
  sameDay('Sun Apr 07 2019 00:00:00 GMT-0300 (Horário Padrão de Brasília)','2019-04-08T03:00:00.000Z'),
  sameDay('Sun Apr 07 2019 00:00:00 GMT-0300 (Horário Padrão de Brasília)','2019-04-13T03:00:00.000Z'),
);

answered Apr 8, 2019 at 16:00

Nino Filiu

18.9k11 gold badges65 silver badges97 bronze badges

Collectives™ on Stack Overflow

How to compare date string using javascript

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related