Update typescript definitions

[MeirionHughes]

• current definitions out-of-date for 2.0 - and for 1.x too in places.

I can pr to defiantly-typed if you'd prefer to keep it there. Alternatively, if you'd like, I could PR into here and make the type definitions a first-class citizen of the package. I'd be happy to maintain.

[ralphtheninja]

I don't have an opinion on where to put the definitions.

@MeirionHughes What would the difference be for people using typescript?

I'm all for helping out typescript users and reducing friction!

@juliangruber @vweevers @mcollina Thoughts?

[MeirionHughes]

Its not that big an improvement. It just means ts users don't have to have to also install @types/levelup - not an issue really.

The main difference is that as being part of the repo it is more likely the definitions can be kept more up to date with lib changes.

[vweevers]

Including it here would also make the definitions versioned, right? Sounds like a good thing

[ralphtheninja]

@MeirionHughes Lets make it happen. Want to be part of level org?

[MeirionHughes]

Sure, can do! :) I'd also like to look at getting es6 Symbol.iterator into here (level-x) too - it would be a natural fit for the underlaying c++ iterator.

[ralphtheninja]

@MeirionHughes Invited! Welcome :)

[liukun]

Great! Looking forward to this!

[MeirionHughes]

Anyone using typescript: #475 could do with a review and potentially a manual test.

[MeirionHughes]

@ralphtheninja I'm still working on this. Currently, the types will work, but anyone wanting to implement the level.AbstractDOWN interface will need to import it from levelup.

So it needs to be moved out somewhere --otherwise leveldown will be importing from levelup-- ideally to something like level-abstract-types to hold the "base" types.

[MeirionHughes]

here is an example of what I'm talking about:

@ralphtheninja so, am I okay to create repo: level/abstract-types?

[vweevers]

Can't we add those type definitions to https://github.com/Level/abstract-leveldown?

[MeirionHughes]

yes, you could; so long as you're happy with things like leveldown and encoding-down having a dev dependency to abstract-leveldown?

[vweevers]

Those directly depend on (and extend) abstract-leveldown :)