Type definition on Dataset.reduce does not match documented (and implemented) behaviour

[halvko]

Which package is this bug report for? If unsure which one to select, leave blank

@crawlee/core

Issue description

According to the documentation "If no memo is passed to the initial invocation of reduce, the iteratee() is not invoked on the first element of the list. The first element is instead passed as the memo in the invocation of the iteratee() on the next element in the list.". But according to the type definitions, reduces second parameter is non-optional, and all items will be of the same type as the parameter passed (e.g. If one passes undefined, the type of the item will be undefined even though it should be Data).

Code sample

const dataset = Dataset.open(/* some dataset id */)

// Causes type-error: `Expected 2-3 arguments, but got 1`
dataset.reduce(async (acc, next) => {
   next 
});

// Causes type-error: `Type 'Promise<Dictionary>' is not assignable to type 'Awaitable<undefined>'` with a ton of explanation - the problem is that the type of `next` is `Dictionary`, whereas reduce is expecting the function to return an `undefined`
dataset.reduce(async (acc, next) => {
   next 
}, undefined);

Package version

upstream

Node.js version

N/A

Operating system

N/A

Apify platform

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I have tested this on the next release

upstream

Other context

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