momentjs keep getting the following error moment.js:Deprecation warning: value provided is not in a recognized RFC2822 or ISO - laravel

Question

I am trying to integrate maddhatter laravel-fullcalendar into a laravel app, I have the calendar working on most browsers but it fails on Internet Exprorer, when I do an inspect I get the deprecation warning.
My array looks like this:
$('#calendar-wean15RN').fullCalendar({
"header":{
"left":"prev,next today",
"center":"title",
"right":"month,agendaWeek,agendaDay"
},
"eventLimit":true,
"defaultDate":"Apr 2017",
"eventColor":"#3c8dbc !important",
"eventBackgroundColor":"#3c8dbc !important",
"eventBorderColor":"#3c8dbc",
"eventTextColor":"#fff !important",
"events":[{
"id":"1557",
"title":"xxx \nHrs worked:6.00",
"allDay":"true",
"start":"2017-04-03T09:00:00+00:00",
"end":"2017-04-03T15:00:00+00:00",
"url":"\/timesheet\/1557\/edit"
}]
}
Not sure what I am doing wrong.
The full error looks like this
Deprecation warning: value provided is not in a recognized RFC2822 or ISO format. moment construction falls back to js Date(), which is not reliable across all browsers and versions. Non RFC2822/ISO date formats are discouraged and will be removed in an upcoming major release. Please refer to http://momentjs.com/guides/#/warnings/js-date/ for more info.
Arguments:
[0] _isAMomentObject: true, _isUTC: true, _useUTC: true, _l: undefined, _i: Apr 2017, _f: undefined, _strict: undefined, _locale: [object Object]
Error
at Function.createFromInputFallback (js/moment.js:314:94)
at configFromString (js/moment.js:2172:11)
at configFromInput (js/moment.js:2541:9)
at prepareConfig (js/moment.js:2524:9)
at createFromConfig (js/moment.js:2491:40)
at createLocalOrUTC (js/moment.js:2578:12)
at Function.createUTC [as utc] (js/moment.js:81:12)
at makeMoment (js/fullcalendar.js:1197:21)
at FC.moment.parseZone (js/fullcalendar.js:1154:9)
at constructor.moment (js/fullcalendar.js:11795:30)
warn # moment.js:287

Answer 1

Change "defaultDate":"Apr 2017" to "defaultDate":moment("Apr 2017", "MMM YYYY").
FullCalendar docs state the defaultDate 's type is Moment.
As the warning says: value provided ("Apr 2017") is not in a recognized RFC2822 or ISO format; so you have to use moment(String, String) parsing function.

Answer 2

As it says here:
https://fullcalendar.io/docs/current_date/defaultDate/
defaultDate should also be an ISO8601 date string.
$('#calendar-wean15RN').fullCalendar(
{"header":{"left":"prev,next today","center":"title","right":"month,agendaWeek,agendaDay"},"eventLimit":true,"defaultDate":"2017-04-03T09:00:00+00:00","eventColor":"#3c8dbc !important","eventBackgroundColor":"#3c8dbc !important","eventBorderColor":"#3c8dbc","eventTextColor":"#fff !important","events":[{"id":"1557","title":"xxx \nHrs worked:6.00","allDay":"true","start":"2017-04-03T09:00:00+00:00","end":"2017-04-03T15:00:00+00:00","url":"\/timesheet\/1557\/edit"}]
}