Uncaught TypeError: Cannot read property 'isSame' of undefined

[lianee]

This issue was previously reported on tempusdominus/bootstrap-4 for a long time but it probably belongs to core:

Reproduce:
go to tempusdominus site, usage, no icon
click on field (it is filled with today's date)
immediately clear this field (don't click anywhere, ctrl-A delete will do)
click outside

console will display:
tempusdominus-bootstrap-4.js:1947 Uncaught TypeError: Cannot read property 'isSame' of undefined at TempusDominusBootstrap4._updateMonths (tempusdominus-bootstrap-4.js:1947) at TempusDominusBootstrap4._fillDate (tempusdominus-bootstrap-4.js:2116) at TempusDominusBootstrap4._update (tempusdominus-bootstrap-4.js:401) at TempusDominusBootstrap4._setValue (tempusdominus-bootstrap-4.js:430) at TempusDominusBootstrap4._change (tempusdominus-bootstrap-4.js:493) at Function._jQueryHandleThis (tempusdominus-bootstrap-4.js:2699) at r.fn.init._jQueryInterface [as datetimepicker] (tempusdominus-bootstrap-4.js:2706) at HTMLInputElement.<anonymous> (tempusdominus-bootstrap-4.js:2734) at HTMLDocument.dispatch (jquery-3.2.1.slim.min.js:3) at HTMLDocument.q.handle (jquery-3.2.1.slim.min.js:3) _updateMonths @ tempusdominus-bootstrap-4.js:1947 _fillDate @ tempusdominus-bootstrap-4.js:2116 _update @ tempusdominus-bootstrap-4.js:401 _setValue @ tempusdominus-bootstrap-4.js:430 _change @ tempusdominus-bootstrap-4.js:493 _jQueryHandleThis @ tempusdominus-bootstrap-4.js:2699 _jQueryInterface @ tempusdominus-bootstrap-4.js:2706 (anonymous) @ tempusdominus-bootstrap-4.js:2734 dispatch @ jquery-3.2.1.slim.min.js:3 q.handle @ jquery-3.2.1.slim.min.js:3 trigger @ jquery-3.2.1.slim.min.js:3 (anonymous) @ jquery-3.2.1.slim.min.js:3 each @ jquery-3.2.1.slim.min.js:2 each @ jquery-3.2.1.slim.min.js:2 trigger @ jquery-3.2.1.slim.min.js:3 _notifyEvent @ tempusdominus-bootstrap-4.js:567 _setValue @ tempusdominus-bootstrap-4.js:425 _change @ tempusdominus-bootstrap-4.js:493 _jQueryHandleThis @ tempusdominus-bootstrap-4.js:2699 _jQueryInterface @ tempusdominus-bootstrap-4.js:2706 (anonymous) @ tempusdominus-bootstrap-4.js:2734 dispatch @ jquery-3.2.1.slim.min.js:3 q.handle @ jquery-3.2.1.slim.min.js:3 tempusdominus-bootstrap-4.js:2501 Uncaught TypeError: Cannot read property 'clone' of undefined at TempusDominusBootstrap4.hide (tempusdominus-bootstrap-4.js:2501) at Function._jQueryHandleThis (tempusdominus-bootstrap-4.js:2699) at r.fn.init._jQueryInterface [as datetimepicker] (tempusdominus-bootstrap-4.js:2706) at HTMLInputElement.<anonymous> (tempusdominus-bootstrap-4.js:2744) at HTMLDocument.dispatch (jquery-3.2.1.slim.min.js:3) at HTMLDocument.q.handle (jquery-3.2.1.slim.min.js:3) at Object.trigger (jquery-3.2.1.slim.min.js:3) at Object.simulate (jquery-3.2.1.slim.min.js:3) at HTMLDocument.c (jquery-3.2.1.slim.min.js:3) hide @ tempusdominus-bootstrap-4.js:2501 _jQueryHandleThis @ tempusdominus-bootstrap-4.js:2699 _jQueryInterface @ tempusdominus-bootstrap-4.js:2706 (anonymous) @ tempusdominus-bootstrap-4.js:2744 dispatch @ jquery-3.2.1.slim.min.js:3 q.handle @ jquery-3.2.1.slim.min.js:3 trigger @ jquery-3.2.1.slim.min.js:3 simulate @ jquery-3.2.1.slim.min.js:3 c @ jquery-3.2.1.slim.min.js:3

[nickalbrecht]

Seems like this is still a bug? Came here from tempusdominus/bootstrap-4#34 as well. Bug is almost 2 years old. I hate pinging authors directly, but maybe you can take a look @Eonasdan and see if if there's a way to correct the library from encountering errors when trying to clear a date?

[jayaddison]

It looks like this is somehow related to bootstrap-4`'s call to this._getLastPickedDate().

That call appears to be routed to the global DateTimePicker that is exported by core (in the originally-referenced 5.0.0-alpha6 here and the current HEAD here).

Is it possible that the semantics and access of the this keyword have changed somehow -- perhaps as a result of changes in the Gruntfile (diff - uglify and nugetpack stand out as changes)?

[tonix-tuft]

@Eonasdan

You can fix it in the following way:

            months.removeClass('active');
            // Check if "lastPickedDate" is truthy otherwise .isSame will throw "TypeError: Cannot read property 'isSame' of undefined"
            var lastPickedDate = this._getLastPickedDate();
            if (lastPickedDate && lastPickedDate.isSame(this._viewDate, 'y') && !this.unset) {
                months.eq(this._getLastPickedDate().month()).addClass('active');
            }

Will create a PR for this.

[Eonasdan]

fixed via #31