TypeScript declarations are failing on iterables

[slavafomin]

Hello!

Thank you for this great library!

However, when I try to use iterable with it, the compilers throws errors:

let i = 1;

const generator = function * () {
  while (true) {
    yield new Promise(resolve => {
      const j = i++;
      console.log('Starting to process #' + j);
      setTimeout(() => {
        console.log('Finished processing #' + j);
        resolve();
      }, 1000);
    });
  }
};

const pool = new PromisePool(
  generator(),
  // Argument of type 'IterableIterator<Promise<{}>>' is not assignable to parameter of
  // type '() => void | PromiseLike<{}>'. Type 'IterableIterator<Promise<{}>>' provides
  // no match for the signature '(): void | PromiseLike<{}>'.
  10
);

pool.start().then(() => console.log('Complete'));

So I have to call it this way in order to suppress the error: new PromisePool(generator() as any, 10);.

Maybe, the declaration should be changed to:

source: () => PromiseLike<A> | IterableIterator<Promise<A>> ?

Thanks!

[slavafomin]

Also, the PromiseLike<A> looks incorrect to me, shouldn't it be () => PromiseLike<A> | null?

[timdp]

Thanks for the feedback! There's another issue around the typings that I haven't been able to get to yet. I didn't write them and I don't know that much about TypeScript, but I've been meaning to get into it. I'll also accept a PR with fixes though!

[slavafomin]

I will try to look into it if time permits. By the way, what other issue you were having with declarations?

[vhfmag]

I just ran into the same problem and fixed it using patch-package, so I could easily submit a PR. What do you think?

[aappddeevv]

I had issues with the typings. I wrote up:

// fix 2018-01-08

export = PromisePool

declare class PromisePool<A> extends EventTarget {
  // skip GeneratorFunction as that is documented to be deprecated starting v3
  constructor(
    source: IterableIterator<Promise<A>> | Promise<A> | (() => (Promise<A> | void)) | A,
    concurrency: number,
    options?: PromisePool.Options<A>
  )

  concurrency(concurrency: number): number
  size(): number
  active(): boolean
  promise(): PromiseLike<void>
  start(): PromiseLike<void>
}

declare namespace PromisePool {
  export interface Options<A> {
    promise?: Promise<A>
  }
}

Added the new index.d.ts to typings/es6-promise-pool then added a reference to the import using tsconfig: "paths": { "es6-promise-pool": ["./typings/es6-promise-pool"]} then imported via import * as PromisePool from "es6-promise-pool" or you could use import PromisePool = require("es6-promise-pool").

But I've not extensively testing the typings though. I needed the result of calling a GeneratorFunction and the others look valid based on reviewing the source code. Note that I just overrode the typings. I use webpack for final bundling.

[aMarCruz]

This definitions also fails with error TS2304: Cannot find name 'EventTarget'