"New Codable" prototype available for feedback

[taylorswift]

@kperryua

Oh this is an interesting concept I hadn’t considered. The intersection of WebAssembly and JS runtimes in Swift is unknown to me. Is there already a bridge in this environment between JS objects and Swift values and a way to call JS functions from Swift?

there is my jss library, which is built atop JavaScriptKit, and provides a serialization-free system for converting structures to and from JavaScript objects.

@kperryua

I can definitely see the value in making encoder/decoder level interfaces that reuse Javascript’s native JSON (de)serialization. However, I think there’s also an interesting tradeoff to consider here. One of the advantages of a decodable type is that it specifies which fields of JSON the client cares about and which can be skipped entirely.

i am not sure i follow. if anything, the tradeoff is reversed, JSON is the format that requires eager parsing of the entire AST, native JavaScript objects on the other hand give you the opportunity to extract data by key without needing to inspect all other fields of an object.

[kperryua (Kevin Perry)]

@taylorswift

i am not sure i follow. if anything, the tradeoff is reversed, JSON is the format that requires eager parsing of the entire AST, native JavaScript objects on the other hand give you the opportunity to extract data by key without needing to inspect all other fields of an object.

Oh I see. This is a scenario where we have already have an in-memory JavaScript object and we want to decode Swift objects from it. I was thinking along the lines of rewriting the parser to take an unparsed string, pass it to JSON.parse() and then decode from the resulting JavaScript objects. Unless there are JavaScript tricks that I'm not aware of (which could VERY easily be the case, considering my inexperience here), the latter has to fully parse AND allocate objects before the decode even starts.