This package is inspired by browser-monads currently without support from the author.
Provide interfaces for the window, document and navigator variables of a webpage.
In functional programming, a monad is an abstraction that allows structuring programs generically. Supporting languages may use monads to abstract away boilerplate code needed by the program logic.
-Wikipedia - Monad (functional programming)
You don't really have to know what a monad is since the variables provided by this library aren't really monads. Let's take a look at the window variable to get a basic understanding. The main purpose of this variable is that it may be a window or it may be nothing. You don't know what it is and you shouldn't really care. In case it is a window, you can use it as you're used to. In case it is not a window, you can still use the same functions on the instance. The caring about the existence of the variable is already taken care of.
This same concept is applicable to the document variable too. You can use the exists function in order to check if the variable exists or you are operating on an instance that contains nothing.
This library makes it possible to use these variables without checks with Gatsby and NextJS. This way of programming splits the defensive part from your own code, since you don't have to care anymore about the environment in which you are running. This makes it especially useful with server-side rendering. More info about the nothing-type can be found here.
import { window, document, exists } from 'browser-monads';
// inside browser ? window.location.href : ''
window.location.href;
// inside browser ? document.getElementById("myId") : ''
document.getElementById('myId');
// inside browser ? true : false
exists(window);