stefanpenner / es6-promise

A polyfill for ES6-style Promises
MIT License
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.d.ts incompatible with TypeScript lib definitions #352

Open michens opened 5 years ago

michens commented 5 years ago
import { Promise as Promise6 } from "es6-promise";

export const error: Promise6<void> = Promise.resolve();
export const error2: Promise<void> = Promise6.resolve();

Sandbox With "lib": ["es5", "es2015.promise"], error fails to compile with the message:

Property 'finally' is missing in type 'Promise<void>' but required in type 'Promise<void>'.

Sandbox With "lib": ["es5", "es2015.promise", "es2018.promise"], error fails to compile with the message:

Type 'Promise<void>' is not assignable to type 'import("/sandbox/node_modules/es6-promise/es6-promise").Promise<void>'.
  Types of property 'catch' are incompatible.
    Type '<TResult = never>(onrejected?: (reason: any) => TResult | PromiseLike<TResult>) => Promise<void | TResult>' is not assignable to type '<U>(onRejected?: (error: any) => U | Thenable<U>) => Promise<U>'.
      Type 'Promise<void | U>' is not assignable to type 'Promise<U>'.
        Types of property 'then' are incompatible.
          Type '<TResult1 = void | U, TResult2 = never>(onfulfilled?: (value: void | U) => TResult1 | PromiseLike<TResult1>, onrejected?: (reason: any) => TResult2 | PromiseLike<TResult2>) => Promise<TResult1 | TResult2>' is not assignable to type '{ <U>(onFulfilled?: (value: U) => U | Thenable<U>, onRejected?: (error: any) => U | Thenable<U>): Promise<U>; <U>(onFulfilled?: (value: U) => U | Thenable<U>, onRejected?: (error: any) => void): Promise<...>; }'.
            Types of parameters 'onfulfilled' and 'onFulfilled' are incompatible.
              Types of parameters 'value' and 'value' are incompatible.
                Type 'void | U' is not assignable to type 'U'.
                  Type 'void' is not assignable to type 'U'.

Sandbox Using es6 (or newer) in place of es5 above gives the same message for error, but adds another failure for error2 with the message:

Property '[Symbol.toStringTag]' is missing in type 'Promise<void>' but required in type 'Promise<void>'

The error2 message was brought up in #300, which was closed without a fix.

It's really frustrating working with libraries that use es6-promise and export the type in their signatures, because you need to wrap the promises or cast away all type safety.

Are there any TypeScript lib configurations that are compatible with this library's typings, or are there any plans to update the definitions to be compatible?