Support Haxe 4 js output with js-es=6 defined

[malec-palec]

Currently, Haxe Modular is unable to process ES6 classes generated by Haxe 4. It breaks on a simple sample:

// Generated by Haxe 4.0.0-rc.3+e3df7a448
(function ($global) { "use strict";
class Main {
    constructor() {
        console.log("src/Main.hx:5:","Hello world!");
    }
    static main() {
        new Main();
    }
}
Main.main();
})({});

with the following error:

C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:2490
  throw err
  ^

SyntaxError: Unexpected token (3:6)
    at Parser.pp$4.raise (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:2488:13)
    at Parser.pp.unexpected (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:623:8)
    at Parser.pp.semicolon (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:600:59)
    at Parser.pp$1.parseExpressionStatement (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:1025:8)
    at Parser.pp$1.parseStatement (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:780:22)
    at Parser.pp$1.parseBlock (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:1040:23)
    at Parser.pp$3.parseFunctionBody (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:2362:22)
    at Parser.pp$1.parseFunction (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:1132:8)
    at Parser.pp$3.parseExprAtom (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:1999:17)
    at Parser.pp$3.parseExprSubscripts (C:\haxe\ModularES6\node_modules\acorn\dist\acorn.js:1872:19)

ES6 classes support will be a nice to have feature, it provides much cleaner js output and works especially great with ES6 modules' import/export statements.

[elsassph]

I was waiting for the output to stabilise before spending time on the parser. Could be worth stating to look into it.

[vrescobar]

I would like to see this one together with es6 as library (no main, using :@expose on some classes). For a larger project with other es6 code which ends up bundled with webpack and post-processed by babel.

Bad enough I can compile everything as a JS and then import that JS, but then I lose all the webpack goodies like automatic rebuild on changes

[vrescobar]

Nevermind... @malec-palec @elsassph yesterday I found myself having this very same problem and I ended up creating a fork of the webpack loader to support raw haxe's builds. It works great with Haxe 4 and ES6 builds but I never tried to split the code into parts since I believe I do not need the feature (I use conditional builds with DCE and webpack passes the whole thing to babel).

https://github.com/vrescobar/webpack-simple-haxe-loader

Since it contains just the minimum amount of features, now it might be trivial to modify the loader to support other variants which deviates from haxe's original behave.

[elsassph]

If you're still interested in ES6 support, the PR is done and I would appreciate if you want to test it.