Return type for an empty Promise.resole() new Promise Typescript

Question

I'm struggling with return type for the current function (example):

const someFunction = () => {
    if (condition) {
        return Promise.resolve()
    }
    return new Promise(resolve => setTimeout(resolve, 1000))
}

How do I define a type that this function returns?

I know that I can set unknown or any , but I'm looking for a cleaner approach.

Answer 1

You can use Promise as generic,

const someFunction = (): Promise<void> => {
    if (condition) {
        return Promise.resolve()
    }
    return new Promise(resolve => setTimeout(resolve, 1000))
}

instead of void you can use another type, based on your Promise resolve

Answer 2

I think, Promise<any> is a good solution here. Since, we haven't defined return type from resolve methods.