We have this code at our work, which i wanted to know the difference between it and just manually typing out the same thing.
const tuple = <T extends string>(...args: T) => args; const strings = tuple( 'blabla', 'default', 'standard' ); export type Strings = typeof strings[number];
When i hover over "Strings", it basically is
type Strings = 'blabla' | 'default' | 'standard'
My question is, why not just simply type out the samething?
type Strings = 'blabla' | 'default' | 'standard';
Instead of all the tuple stuff? I can’t see a difference, but if someone could explain why we’re using this Tuple function that would be great
If you don’t export
strings then it is definitely better to directly declare the type. In some cases you also need the values though, and using that
tuple function saves you from having to specify each one twice.
There’s a simpler and safer way to do this though:
export const strings = [ 'blabla', 'default', 'standard' ] as const; // type: readonly ["blabla", "default", "standard"] export type Strings = typeof strings[number] // type Strings = "blabla" | "default" | "standard"
strings readonly, so you can’t do an unsound
strings.pop() for example.
Answered By – Oblosys
Answer Checked By – Timothy Miller (BugsFixing Admin)