Existential operator can be used as optional chaining operator but also in trailing position ie: if window? env = 'browser' ... is equivalent

Existential operator can be used as optional chaining operator but also in trailing position ie: if window? env = 'browser' ... is equivalent to: if (typeof window !== "undefined" && window !== null) { env = 'browser' ... } But yes, nullish coalescing and optional chaining that came from existential operator are good.