On a personal note, I'm not sure that it's helpful to have the fat arrow used for what seems to me like two different things: separating the return type from the parameters in the declaration and ...

A parameter is declared within the parentheses of a function's header. These declarations specify the name and, in statically ...

The TypeScript datatyping support not only applies to simple variables, it also supports you when doing clever things with functions. Specifically, TypeScript ensures you create reliable code when ...