Compiling to ES6?

Question

How would I compile

export default User
import socket from "./socket"

this ES6 javascript function with haxe?

import socket from "./socket"
let User = {
    init(socket, element) {
        if (!element) {
            return
        }
        let userId = element.getAttribute("data-id")
        userId= Math.random()
        socket.connect()
        this.onReady(userId, socket)
    }
}
export default User

Answer 1

I actually had the same need a while ago, in order to integrate with Ember 2.0/Ember CLI. I didn't find a way with pure Haxe, the only alternative is to either:

1) Build a custom js generator - clunky because you lose the goodies of the built-in js generator since there's no granular control over what features you use - it's all or nothing - i.e you can't only change the output of a certain expression/type in the AST, and you can't reference the built-in generator and delegate to it when needed.

2) A pre-processor that parses the hx file, removes the ES6 code, compiles the file, and adds the ES6 code back, clunky as well, but might work.

3) Hack the OCAML code for the compiler and add some kind of class-level metadata tag, something like @:ESImport("import {foo} from bar"), @:ESExport("export default foo"). This could also be done with #1 (custom js gen), but by modifying the OCaml code, you get to keep the built-in js gen.

I've given up on integrating Haxe code with ES6 for now, I wish Haxe had better build-in support for ES6 (i.e an ES2016 generator) or more granular hooks for the JS Custom generator API.

As a reference, here's my message to the Haxe mailing list, about this very issue: https://groups.google.com/forum/#!topic/haxelang/jSTkkaNgfB8.