(value: never, message?: string | undefined): asserts value is never Beyond terseness, this is useful because throw is not an expression,
and therefore can't be used in places like Svelte markup without a workaround,
at least until this proposal is accepted and widely available:
https://github.com/tc39/proposal-throw-expressions
value
type
nevermessage?
type
string | undefinedoptional
returns
void