isDateString does not work properly

[Julio-Vasquez]

** I think it doesn't work properly.**

using postman, I send the following data.

The result:

The class:

I got to that, I thought, maybe it's the format:

The result :

I am making a mistake or maybe isDateString does not work properly

I am using class-validator 0.11.0

I apologize if I'm not very clear, my English is bad.

[BojanKogoj]

Looking at documentation @IsDateString() verifies date and time

Checks if a string is a complete representation of a date (e.g. "2017-06-07T14:34:08.700Z", "2017-06-07T14:34:08.700 or "2017-06-07T14:34:08+04:00").

[Julio-Vasquez]

I have performed the tests with these values, but I still have the same error

[vlapo]

We have some discussion about this validator https://github.com/typestack/class-validator/issues/412.

Please try @IsISO8601() validator and use date in format 2019-10-04;

[cjancsar]

@vlapo and what if we need datetime validation?

[msrumon]

This is also bugging me...

[Julio-Vasquez]

This is also bugging me...

use @IsISO8601() it worked for me

[msrumon]

@Julio-Vasquez I tried already, didn't work. Are you sure it works with latest version?

[Julio-Vasquez]

I did this example with version 0.13.1

[kodeine]

I am getting must be a valid ISO 8601 date string for "2021-03-22T17:11:52.279Z"

[AdamHavlicek]

Well it seems it's issue of dependency library (validator).

[braaar]

Any news on this? I am getting this validation error, on version 0.13.2 (same as @kodeine):

{
          "value": "2022-04-16T00:00:00.000Z",
          "property": "myDate",
          "children": [],
          "constraints": {
            "isIso8601": "myDate must be a valid ISO 8601 date string"
          }
}

I tested this example against the regex in the actual validator code, and it matches that. So the regex itself seems fine.

[braaar]

I have done some tinkering around and have learned something that I think could be valuable for others.

I was trying to validate a date which was sent as a string from the client application into a graphQL mutation, parsed by GraphQ as a Date object in the GrapQL input type in the backend, and then validated as a Date object.

The only stage where the date was a string was in the frontend (and in the request body), but in my backend, where the validation takes place, the date was never represented as a string.

If we look at this console.log of my object (in the backend, right before applying validation), we can see that the date is not a string due to the lack of quotation marks:

{
  complete: false,
  customer: '123abc,
  assignmentNumber: '3131111',
  myDate: 1970-01-01T00:00:00.000Z,
}

The error message's string representation of the value makes it look like the date is a valid ISO 8601 date string, but it is in fact a date object that cannot be validated as a string.

[braaar]

The solution in my case was to use @IsDate instead of @IsISO8601.

[seanmoghadam]

Just made an update from 0.9.1 to 0.13.2. The old code with the same validation worked - now it's not working anymore. Issue still open:

{
	"error": "Validation Error",
	"status": 400,
	"messages": [
		{
			"key": "dates",
			"messages": [
				"dates must be a valid ISO 8601 date string"
			],
			"value": [
				"2025-07-30T16:25:43.511Z"
			]
		}
	]
}

Validation Block:

@IsNotEmpty({ message: '...' })
@IsDateString({ each: true, message: '...' })
dates: string[];

Our use case needs an ISO timestamp and not just a date, so upper solutions are not valid for us. Downgrading to 0.9.1 is also not an option due to security vulnerabilities.

[subashdbc]

Any update on this decorator @IsDateString()?

[seanmoghadam]

I took a look at the validatorjs lib and checked the two regex they use internally:

const iso8601 = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W([0-4]\d|5[0-3])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[1-6])))([T\s]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$/;

// same as above, except with a strict 'T' separator between date and time
const iso8601StrictSeparator = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W([0-4]\d|5[0-3])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[1-6])))([T]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$/;

Source: https://github.com/validatorjs/validator.js/blob/master/src/lib/isISO8601.js

Both of them look actually fine. I tested them with: https://regex101.com/

and 2025-07-30T16:25:43.511Z was valid...

Now, what I will try in the next days is to pass down the iso8601StrictSeparator option from ValidatorJS. No Idea if that works

EDIT: okay the option is not yet implemented in the current validatorjs version used by class-validator - the regex there just looks like that:

var iso8601 = /^([\+-]?\d{4}(?!\d{2}\b))((-?)((0[1-9]|1[0-2])(\3([12]\d|0[1-9]|3[01]))?|W([0-4]\d|5[0-2])(-?[1-7])?|(00[1-9]|0[1-9]\d|[12]\d{2}|3([0-5]\d|6[1-6])))([T\s]((([01]\d|2[0-3])((:?)[0-5]\d)?|24:?00)([\.,]\d+(?!:))?)?(\17[0-5]\d([\.,]\d+)?)?([zZ]|([\+-])([01]\d|2[0-3]):?([0-5]\d)?)?)?)?$/;

Which is still fine....

[simplenotezy]

The solution in my case was to use @IsDate instead of @IsISO8601.

The problem with this is that it does not respect dates with timezones. So If I send in: 2022-09-15T17:05:58.077393Z it will return a javascript Date, in UTC

[jackykwandesign]

The solution in my case was to use @IsDate instead of @IsISO8601.

Same issue here, seems GQL will parse ISO date string into Date instance by nature of DateTime Scalar, So using IsDate should be final answer if working with GQL

[NoNameProvided]

For simple dates I cannot reproduce, the following works with the latest 0.13.2:

import { IsDateString, IsISO8601, validate } from 'class-validator';

class MyPayload {
  @IsISO8601()
  @IsDateString()
  field: string;

  constructor(field: string) {
    this.field = field;
  }
}


validate(new MyPayload('2009-10-01')).then(console.log); // returns no validation errors
validate(new MyPayload('2022-04-16T00:00:00.000Z')).then(console.log); // returns no validation errors

For arrays I can reproduce:

import { IsDateString, IsISO8601, validate } from 'class-validator';

class MyPayload {
  @IsISO8601({ each: true })
  @IsDateString({ each: true })
  field: string[];

  constructor(field: string[]) {
    this.field = field;
  }
}


validate(new MyPayload(['2009-10-01'])).then(console.log); // validation error
validate(new MyPayload(['2022-04-16T00:00:00.000Z'])).then(console.log); // validation error

This is a bug.

[NoNameProvided]

Seems the array one has no open bug report.

[NoNameProvided]

The confirmed bug is now tracked in https://github.com/typestack/class-validator/issues/1843.

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