Property 'allSettled' does not exist on type 'PromiseConstructor'.ts(2339)

Question

I\'m trying to use the Promise.allSettled API with TypeScript. Code here:

server.test.ts:

it(\'shou         


        

Answer 1

The types for Promise.allSettled() were only merged in January, and will apparently be released in TypeScript 3.8.

As an interim solution, you can declare a mock-ish type for the function yourself:

declare interface PromiseConstructor {
    allSettled(promises: Array>): Promise>;
}