Combine fails on large unions with object API but works via multiple arguments API

[7rulnik]

Missing/Incorrect APIs

The example below fails with Type instantiation is excessively deep and possibly infinite.(2589).

It's obvious that this problem is related to Currency variations. It works with 14 elements, but not more. I also tried 4.5.0-beta with Tail-Recursion Elimination but the result is the same.

Also, it could be workarounded via multiple arguments, but it leads to more verbose code.

import { createStore, combine } from 'effector';

type Currency = 'usd' | 'eur' | 'cny' | 'uah' | 'byn' | 'thb' | 'rub' | 'azn' | 'kzt' | 'kgs' | 'uzs' | 'tzs' | 'kes' | 'zar' | 'ron' | 'mdl' | 'ils' | 'inr' | 'pln' | 'chf' | 'gbp';


const initialValue = 'usd' as Currency;

const $currency = createStore<Currency>(initialValue)

type AutosearchTrigger = {
  currency: Currency;
};

// Will fail with «Type instantiation is excessively deep and possibly infinite.»
const $autosearchTrigger = combine<AutosearchTrigger>({
  currency: $currency,
});


const $autosearchTriggerViaTuple = combine<Currency, AutosearchTrigger>($currency, (currency) => ({
  currency
}));

Playground Link: Provided

Relevant documentation

combine(...stores, fn) works
combine({ A, B, C }, fn?) doesn't work

[sergeysova]

It is better not to pass generic arguments to combine.
Try to remove them and left all work to typescript.

But without generics looks very interesting.

Thank you for your report!

[sergeysova]

Similar problem: microsoft/TypeScript#30188 (comment)

[zerobias]

Fix will be published in the next minor release but looks like typescript 4.5.0 already added support for that case on their side

[7rulnik]

@zerobias I can still reproduce it with 4.5.2
https://www.typescriptlang.org/play?ts=4.5.2#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

Thanks, will wait for release