Unhandled error being thrown in Safari/MacOS

### I'm Submitting a ...

```
[x] Bug report
[ ] Feature request
[ ] Support request
```

### Steps to Reproduce

The issue is only appearing for certain users, specifically in Safari. Simply navigating to a page with a DateTime component causes an unhandled error to be thrown.

### Expected Results
This appears to be an issue that should be caught internally - nothing appears to be abnormal in our code base looking through the stack trace.

### Actual Results
An unhandled error is thrown:
TypeError: undefined is not an object (evaluating 'this.getRow(n,a++).push')
it appears the variables **n** as well as **a** are both undefined. The code is minified, so I don't know have much further than that. Is there perhaps some missing type checking/validation?

### Other Information (e.g. stacktraces, related issues, suggestions how to fix)
The react-datetime code causing the issue is the following:
```
{
key: "renderDays",
value: function value(e, t, n) {
var r = [[], [], [], [], [], []],
o = e.clone().subtract(1, "months");
o.date(o.daysInMonth()).startOf("week");

for (var a = o.clone().add(42, "d"), i = 0; o.isBefore(a);) {
// THE FOLLOWING LINE THROWS:
this.getRow(r, i++).push(this.renderDay(o, t, n)), o.add(1, "d");
}

return r.map(function (e, t) {
return c.a.createElement("tr", {
key: "".concat(a.month(), "_").concat(t)
}, e);
});
}
},
```