min and max validators should ignore date values instead of trying to typecast them into numbers and getting NaN, causing validation to fail

[shahmirn]

According to MDN at https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input, min and max can take a date-time value.

My use case is I have an input field with the HTML:

                        <input type="date"
                            id="calculationDate"
                            class="form-control"
                            name="calculationDate"
                            min="1900-01-01"
                            minDate="1900-01-01"
                            max="2099-12-31"
                            maxDate="2099-12-31"
                            [(ngModel)]="model.calculationDate"
                            #calculationDate="ngModel"
                            required
                            date/>

I use min and max so that when chrome displays its built-in calendar widget, dates before min and after max are grayed out / unselectable.

However, when I have this HTML, the min and max validators end up trying to convert these values into a number, which results in NaN, which causes the validation to fail.

To fix this issue, if the min or max value isNaN and is a date, then simply return null. The validtion of these fields are handled by minDate and maxDate

[shahmirn]

@yuyang041060120 please take a look

[Chuvisco88]

@shahmirn You did not have to the problem I described in #59?

[shahmirn]

@Chuvisco88 I didn't