How can I provide a generic string array to a function argument and use the generic type in the other function argument?
I want to achieve something like this below:
type Custom<T> = {
hello: string;
world: T;
};
declare function builder<T extends readonly string[]>(
input: T,
arg: () => Custom<T>,
): void
builder(['hello'] as const, () => ({
hello: 'some text',
world: ['1', '2', '3'], // <-- This should fail, as it's not 'hello'!
}));
You don't really need to use as const here. You can use variadic tuple types to infer input as a string tuple.
type Custom<T extends string[]> = {
hello: string;
world: [...T];
};
declare function builder<T extends string[]>(
input: [...T],
arg: () => Custom<T>,
): void
Or you could use T as just a string type and type input and world as T[].
type Custom<T extends string> = {
hello: string;
world: T[];
};
declare function builder<T extends string>(
input: T[],
arg: () => Custom<T>,
): void
