Improve typings for computedFn

[mixail-novikov]

I notice that computedFn does not infer types from passed callback. I've been fix it, please review.

[coveralls]

Coverage remained the same at 94.118% when pulling e98b510 on mixail-novikov:master into fe9b9ec on mobxjs:master.

[danielkcz]

I wonder why there are so many differences. Are you using other auto formatter than Prettier? Can you try to do a change without any formatting changes, please?

[xaviergonz]

I think what is actually wrong is the setting on prettierrc
https://github.com/mobxjs/mobx-utils/blob/master/.prettierrc

it establishes 4 spaces, while the file is obviously formatted as 2

Maybe there should be a commit just running prettier over all files previous to this commit to ensure consistency?

[xaviergonz]

lgtm

[danielkcz]

@xaviergonz Do you see why the coverage drop? If it's about fixing types only, it shouldn't affect coverage, right? I am failing to see it in that reformatted code.

I agree we should fix prettier and probably add Husky.

[mixail-novikov]

Thank you for the fast review! I've made changes, please review it again.

[dgreensp]

I'd love to see this released!