[feature] live js and css reloading using server sent events

[yoshuawuyts]

should wrap this https://github.com/chinedufn/hot-app-replacement by @chinedufn

[marionebl]

Appears to compete with #34, #1.
Some history and discussion about HMR approaches in #45 (browerify-hmr vs custom SSE)

In order to implement this there are changes that need to be landed and released:

• Landed barracks#!59
• Released barracks#!59
• Landed choo#!203
• Released choo#!203

---

Example of choo entry point with HMR enabled:

const html = require('choo/html')
const hmr = require('choo-hmr')
const choo = require('choo')

const app = choo()
app.use(hmr())

app.router([ '/', () => html`<div>hello world</div>`])

const tree = app.start()
document.body.appendChild(tree)

[yoshuawuyts]

related choo issue choojs/choo#295

[yoshuawuyts]

implementations:

• https://github.com/bengourley/choo-resume
• https://github.com/bengourley/hot-rld

[mattdesl]

You might be interested in following some of the recent LiveReload changes in budo:
mattdesl/budo#194

For example, you can use this in the client to force a style sheet to reload smoothly across all modern browsers:
https://www.npmjs.com/package/reload-css

I chose to go with WebSockets for budo just because they are supported in Edge/IE. I'd be curious to know if SSE has some advantage for live reload purposes, though.

[yoshuawuyts]

done!

[laduke]

how do you turn it on?

[mikker]

@laduke With https://github.com/yoshuawuyts/choo-reload