How to generate N-length tuple of same item in typescript for function arguments

Question

Is there a way to quickly pass multiple null (or any other) arguments to function call in typescript. Given example below I need only first argument and others require to be some type or null. Is there any way to generate typescript type for N-length of tuple so I can create a helper function which will return that type tuple. Something like below.

const functionToCall = (arg0: string | null, ..., arg50: string | null) => {
    // ....
}

const getNLengthOfValue = (value: any, repetitions: number) => {
    return [...new Array(repetitions)].map(() => value);
}

functionToCall("some value", ...getNLengthOfValue(null, 50));

P. S. I know I can use rest param, but my question is not about API, this is just a rough example. I want to know how to create type for N length tuple of same type items and how to return it from function.

Answer 1

You can use an rest parameter like this:

const functionToCall = (arg0: string | null, ...restArgs: (string | null)[]) => {
    // ...
};