Typo?

[IAmAnubhavSaini]

})(typeof window !== "undefined" in README

[ljharb]

Nope - if you look a few lines down, there's a matching closing paren.

[IAmAnubhavSaini]

// If we're in a browser, the global namespace is named 'window'. If we're
// in node, it's named 'global'. If we're in a shell, 'this' might work.
})
(typeof window !== "undefined" ... );

Check third line.