feat:ContractSpec class to parse ScVals

[willemneal]

This adds a new ContractSpec class which is comprised of the spec entries of a contract. This allows the internal user defined types to be accessible making the parsing to and from XDR more accurate. This should be moved to the js-stellar-base, but for now it is best served here for the type support.

This should replace the current parsing logic in the TS bindings currently living in the soroban-tools repo.

Also discussion here: https://gist.github.com/tyvdh/9391482f7490b085b283ea96d2f50b11

[paulbellamy]

A couple small suggestions, but looks awesome.

[socket-security]

New dependencies detected. Learn more about Socket for GitHub ↗︎

Packages	Version	New capabilities	Transitives	Size	Publisher
@types/mocha	10.0.1	None	+0	96.3 kB	types
stellar-base	10.0.0-soroban.7	None	+4	8.49 MB	stellar-npm-ci

[willemneal]

@Shaptic @paulbellamy I removed having the optional typeDef and it simplified everything. I was also able to switch all string comparisons to value comparisons which should improve performance (though I'm sure that's not the bottleneck currently for devs).

[willemneal]

@paulbellamy I went with still having the base64 as it was easiest to copy over from the soroban-cli tests we added for the bindgen. For now I can regenerate the json file manually, but I'll add a script to do it soon.

[willemneal]

@Shaptic Updated after your comments. Definitely could test more errors, but I think the tests are good enough for now

[Shaptic]

Really really awesome work! Excited to get this across the finish line.

Last question: this uses futurenet-compatible XDR, right? I think yes based on the package.json but I want to confirm.

[willemneal]

Yep! That is why I ported the CLI's tests! But using this to do the parsing of the generated bindings I was able to get a roundtrip with futurenet (we don't have the tests in CI in that repo yet because we don't want to depend on CI).

[Shaptic]

Love it! So are we ready to merge, then? It'd be awesome if you could add a brief changelog entry that matches the format of the others, then I can hit the button