Make toJS/fromJS somehow optionally preserve Set/OrderedMap types about immutable-js

[sophiebits]

I was just wondering about this too today. Maybe it makes sense to recommend something like transit-js for serialization though – @swannodette's blog post serializes into regular JSON objects and arrays but I think it's easy to switch the tags.

[Tvaroh]

Hi, Ben. I read David's post this morning. While I like this stuff I don't think transit can replace JSON for server communication. One can't just take his REST endpoint and migrate it to another transport. Most people would stay with JSON though.

[swannodette]

@Tvaroh the point of my post was that the endpoint can appear to be a normal JSON even though it's actually Transit JSON. For example you could follow my post exactly and just add read/write handlers for Immutabe Sets and it will just work - Transit represents sets today as {"~#set": [1,2,3]} - perfectly valid JSON and no one needs to be the wiser. Ordered collection types don't present any challenges - you can install your own tag ~#orderedSet and ~#orderedMap, the wire rep of the data is an array so order on the read side can be preserved.

All that aside I do think this ticket is asking for something that seems outside the scope of Immutable - serialization concerns like this seems best handled elsewhere and if not by Transit by some other means.

[Tvaroh]

@swannodette sorry, I don't understand. How my Scala backend can start working with transit? Immutable provides fromJS/toJS - and I don't think it's outside of its scope to do this conversions correctly for supported types.

[swannodette]

@Tvaroh Scala users can use https://github.com/cognitect/transit-java for now. I've expressed the full extent of my opinion here :)

[Tvaroh]

That's what I'm talking about. Who wants to refactor REST backend to support transit?

[swannodette]

@Tvaroh I guess don't see what refactoring needs to be done - at least in my experience a REST backend often emits response as .toXML or .toJSON regardless of language. You can add transit.write to that list and in fact reuse all of your existing JSON infrastructure.

Of course a backend may not be so be clean warranting front-end ad-hoc solutions as the kind suggested in this thread. That to me is a warning sign.

[leebyron]

Yeah, I think this is out of scope for immutable-js because it's not intended to be a transport and there is no standard for this (and I don't want to force a proposed standard). For example, what if someone sets the key "type" on a map/set? There's then a collision.

I do recommend using something like transit-js for this. Or, a function to do this should be pretty straight-forward. Then our fromJS method should already support this by providing a converter function as the 2nd arg and checking for this "type" key.

[Tvaroh]

Okay guys, I finally agreed. Will give transit-js a try.