Is it possible to restrict number to a certain range
If You have small range, you can always write something like:
type MyRange = 5|6|7|8|9|10
let myVar:MyRange = 4; // oops, error :)
Of course it works just for integers and is ugly as hell :)
No it's not possible. That kind of precise type constraint is not available in typescript (yet?)
Only runtime checks/assertions can achieve that :(