Haxe-JS code-splitting and hot-reload for modular applications

To install, run:

haxelib install modular 0.10.14 

See using Haxelib in Haxelib documentation for more information.

Haxe Modular

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Code splitting and hot-reload for Haxe JavaScript applications.


If you use Haxe for JavaScript, directly or indirectly (React, OpenFl,...), then you probably want to:

  • make your web app load instantly,
  • make your HTML5 game load quicker,
  • load sections / features / mini-games on-demand.

Haxe has an excellent, compact and optimised JS output, but it's always a single file; even with good minification / gzip compression it can be a large payload.

Modular can split gigantic Haxe-JS outputs into load-on-demand features, without size/speed overhead, and without losing sourcemaps.


import MyClass;
load(MyClass).then(function(_) {
	var c = new MyClass();

The approach is to reference one class asynchronously in your code:

  • at compile time, the dependency graph of the class is built and one additional JS file will be emitted (bundling this class and all its dependencies),
  • at run time, when the aynchronous reference is evaluated, the additional JS is loaded (once) automatically.

Where to start?

There are 2 ways to use Haxe Modular, depending on your project/toolchain/goals:

  1. standalone Modular; zero dependencies, for any Haxe-JS project,
  2. Webpack Haxe Loader; leverage the famous JS toolchain.

In both cases, it is advisable to read about the technical details:

What is the difference?

Both solutions:

  • use Modular splitting under the hood,
  • split automatically using a single hxml build configuration,
  • support NPM dependencies,
  • allow hot-reloading of code.

What should I use?

  1. Standalone Modular is an easy, drop-in, addition to a regular Haxe JS build process - it is very lightweight and unobstrusive, and you don't need to learn Webpack.

Using NPM modules however requires a bit of ceremony: all the NPM dependencies have to be gathered (manually) in a libs.js which is loaded upfront.

  1. Webpack Haxe Loader is a more powerful setup but you'll have to learn Webpack. Webpack is a complex and large system offering vast possibilities from the JS ecosystem.


Q: Where can I get more help? I have questions / issues...

Q: Is it only for React projects?

  • Of course not; anything targeting JavaScript can use it.
  • However it does offer React-specific additional features for code hot-reloading.

Q: Is it possible to minify the code?

Q: Can I extract a library/package from my code?

  • Yes: you can split libraries, but for technical reasons, extracting a library (e.g. many classes used across the application) has some limitations.

Q: Can I still use the includeFile macro to inject JS code in the output?

  • Yes, but only when the code is inserted at the top of the file; this is the default position when using --macro includeFile('my-lib.js').
3 weeks ago

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