"includes" not supported by IE 11. Use indexOf or "in includes" instead.

[SherylHohman]

Bug In IE11 the following error occurs:

Object doesn't support property or method 'includes'

Reason:
includes is not supported in IE.

Proposed solution:
Can it be replaced by indexOf ? or array-includes ?
IE11 - Object doesn't support property or method 'includes ...

For context, airbnb/react-dates implemented a fix for this same issue.