# Hot module replacement with browserify/watchify or webpack

Using hot reloading while developing can improve your workflow.
No more clicking through your application to a particular state each time you change the rendering code!

## Running the examples

This example must be run standalone, instead of through the usual `npm run examples` in this repository's root.
To install and run:

    npm install

    // for browserify
    npm run hot-browserify

    // for webpack
    npm run hot-webpack

Edit [package.json][] if you want to run on a different port.
If you're running inside a container or VM, add `--host 0.0.0.0` (webpack) so you can access the dev server from your host machine.

Try clicking to increment the counter, then edit [render.js][]!
Your changes should instantly appear on the page without refreshing or upsetting the counter's value.
Note that if you edit [browser.js][], your page will refresh and your state will be reset (only using webpack).

[package.json]: ./package.json
[render.js]: ./render.js
[browser.js]: ./browser.js

## How it works

### webpack
Running `webpack-dev-server` with the `--hot` argument enables [hot module replacement][], but to make use of it you need to add a little bit of code to your application.
When webpack detects a file has changed, `module.hot.accept` gets a chance to 'claim' the reload and prevent the page from refreshing as it usually would.
We use that opportunity to replace the function the app uses to render.
We have to be careful to not reseat any references - so we pass a function that doesn't change to `hg.app` (i.e. `App.render`), but inside that function, we call a function which may change at runtime.

### browserify/watchify
The main difference to webpack is that browserify does not come with a dev-server which is why we use [http-server][] to host our example. Other than that it works quite similar. Under the hood [browserify-hmr][] imitates webpack's hot module replacement.

[hot module replacement]: https://github.com/webpack/docs/wiki/hot-module-replacement-with-webpack
[http-server]: https://github.com/indexzero/http-server
[browserify-hmr]: https://github.com/AgentME/browserify-hmr