Typescript generic Rest operator with corresponding callback

Issue

i have recently picked up Typescript because it seemed interesting. I have used generics in C# before and managed to do quiet a few things with generics in Typescript but now im stumped for the following use case:

I have a generic function that takes in any number of Rest arguments. These arguments are than passed to a callback function which is also provided. But i cannot seem to figure out how to make the typescript compiler accept the types i provide to implicitly be passed into the callback function.

async SampleFunction(
    cb: () => void,
    ...args: any[]
)

with this as sample usage:

let stringVariable = "lorem";
let numberVariable = 8;

SampleFunction(
    (stringArg, numberArg) => {},
    stringVariable,
    numberVariable,
)

This example results in arguments that think they are implicitly type 'any'.

my question hereby is: how can i make this function definition so that i could pass in any aditional arguments which then get their type passed into the callback function as they are passed in the same order.

Solution

Thanks to the help of @Etheryte i got onto the right search track.

I found the sollution i wanted which is:

function SampleFunction<T extends any[]>(
    cb: (...args: T) => void,
    ...args: T
): void {}

let stringVariable = 'lorem';
let numberVariable = 8;

SampleFunction(
    (a, b) => {}, 
    stringVariable, 
    numberVariable
);

This implicitly passes the right argument types from the function into the callback

Answered By - jetenergy