Knockout date validation not working correctly

Question

I need to validate date in localized format (SK) and it is not possible with knockout validation.

I am using: Durandal 1.2.0 Knockout 2.3.0 Knockout validation https://g

Answer 1

Very late for this, but just want to share my updates on @ChoptimusPrime's answer. Not hard-coding the format:

ko.validation.rules['dateAndFormat'] = {
    validator: function (val, format) {
        return ko.validation.utils.isEmptyVal(val) || moment(val, format).isValid();
    },
    message: 'Please provide a valid date.'
};
ko.validation.registerExtenders();

Answer 2

The only working solution I have for now is below. The problem with this validator is that it also validates default(EN) date format as valid, so I have to add a IF to return this as invalid date format.

var dateValidator = function (val) {
            if (!val)
                return false;
            if (moment(val, 'DD.MM.YYYY HH:mm').isValid()) {
                return true;
            }
            else
                return false;
        };


var startDate = ko.observable().extend({ validation: { validator: dateValidator, message: 'Start of task is not in correct format.' } });

Answer 3

A little late by why not... The date rule does seem a bit too permissive for my uses as well. If you like moment but want something cleaner for the caller, add your rule to the validation.rules object:

ko.validation.rules['simpleDate'] = {
    validator: function (val, validate) {
        return ko.validation.utils.isEmptyVal(val) || moment(val, 'MM/DD/YYYY').isValid();
    },
    message: 'Invalid date'
};

And then use it like:

var someDate= ko.observable().extend({ simpleDate: true });