Option to control precision of newDate returned

[stansey]

Feature Request

Add a precision option prop to the DateTimePicker component. (Or remove extraneous seconds from returned newDate)

Currently the DatePicker seems to return a timestamp with a random number of seconds. Ex: When I select: Thu Jan 2 12 20 PM I get a newDate of: 2020-01-02T17:20:28.000Z When I select Tue Dec 31 11:14 AM I get a newDate of: 2019-12-31T16:14:28.000Z

For some reason the returned date has a random extra 28 seconds. I think on other runs I have observed different numbers of excess seconds. Sometimes the returned newDate will be before the date I want and sometimes it is after.

<DateTimePicker
      isVisible={isVisible}
      mode={mode}
      onConfirm={timethingy => {
        console.log("GLB", timethingy);
        onPressConfirm(timethingy);
      }}
      onCancel={onPressCancel}
      date={typeof selectedMs === "number" ? new Date(selectedMs) : undefined}
      titleIOS={titleIos}
      is24Hour={is24Hour}
    />

Why it is needed

The extra seconds added to the selected date time make code less predictable and I can't think of a reason why the current behavior is desirable. I guess maybe it's an artifact of the date library or timezone conversion?

Possible implementation

When converting the user selected date and time to a date object, either set the precision to ignore seconds or round to the nearest minute.

Code sample

<DateTimePicker
      isVisible={isVisible}
      mode={mode}
      onConfirm={newDate => {
        onPressConfirm(newDate);
      }}
      onCancel={onPressCancel}
      date={typeof selectedMs === "number" ? new Date(selectedMs) : undefined}
      titleIOS={titleIos}
      precision={is24Hour}
    />