Functions in TypeScript aren't handled the way you'd expect, based on any other language (including JavaScript). ... To actually execute the function and store its results in FirstNameOther, I have to ...

Also in TypeScript 4.9, the in operator has been made more powerful when narrowing types that do ... the forEachChild function has been rewritten to use a function table lookup instead of a switch ...

TypeScript 5.4, a planned update to the strongly typed JavaScript variant from Microsoft, is now generally available. New capabilities in version 5.4 include preserved narrowing within function ...