Determines if the current runtime environment is a browser so that front-end modules can run on the server (Node) without throwing errors.
Array.prototype.includes() on the
typeof values of both
document (globals usually only available in a browser environment unless they were explicitly defined), which will return
true if one of them is
typeof allows globals to be checked for existence without throwing a
If both of them are not
undefined, then the current environment is assumed to be a browser.
const isBrowser = () => ![typeof window, typeof document].includes("undefined");
isBrowser(); // true (browser)
isBrowser(); // false (Node)