Support for HashMap?

[hoang17]

Hi,

First of all, thank you for the great library! I am using this for a personal project. Any chance for supporting HashMap?

Best regards,

[twop]

Hey @hoang17 I didn't have immediate need at the time and decided to defer adding new types until the need arrives.

It is possible that the time is now :)

There are two main questions how to approach this:

1. What data structure will be used in JS?
2. What kind of limitations/restrictions need to be in place?

They are kinda related to each, and here is my thoughts:

• I would love to avoid building custom types (like immutablejs or mobx-state-tree do).
• That leaves us either with native Map or plain object
• Out of these I prefer native Map
• which can potentially use any types for keys but in our use case it boils down to 'number' (f32, f64, i32) or string
• at the time that restriction seemed to be major enough to defer the decision until I get more info.

I actually did a work around for one of my use cases: Have a collection of Vec(Tuple(Key, Value)). In reality that is how serde internally transforms maps, of course, that incurs significant overhead on both sides to transform data to a 'Map' structure. For me it worked fine because there were not many values passed in.

@hoang17 pls let me know what are your thoughts and could you tell me more about your use case? I think adding a HashMap shouldn't be too hard, I probably can hack it within a day with the Key limited to numbers or strings.