cmmartin/server.js

## server.js
import koa from 'koa'
import router from 'koa-route'
import streamView from './stream-view'

const app = koa()
const toJS = str => JSON.parse(str)
const toJSON = js => JSON.stringify(js)

// stream an html page with asynchronous data
app.use(router.get('/html/:title', streamView('html', function* (title) {
  yield `
    <!DOCTYPE html>
    <html>
      <head>
        <title>${ title }</title>
        <meta charset="utf-8">
        <link rel="stylesheet" href="/bundle.css?${this.request.querystring}" />
      </head>
      <body>
        <div class="mount-node"></div>
        <script type="text/javascript">
          window.props = `; yield getProps(this.request.query); yield `;
        </script>
        <script type="text/javascript" src="bundle.js"></script>
      </body>
    </html>
  `
})))

// stream a json file
// potentially useful for condensing many requests into one
app.use(router.get('/all-the-things.json', streamView('json', function* (title) {
  yield getProps(this.request.query)
})))

function *getProps(queryParams) {
  return toJSON({
    foo: yield fetch(`/some/api`).then(toJS),
    bar: yield fetch(`/some/api/${queryParams.thing}`).then(toJS),
    baz: yield fetch(`/some/api/${queryParams.anotherThing}`).then(toJS)
  })
}

app.listen(3000)

## stream-view-middleware.js
import StreamView from './stream-view'

export default function getMiddleware(type, chunkGenerator) {
  return function *(options) {
    this.type = type
    this.body = new StreamView(this, chunkGenerator.bind(this), options)
  }
}

## stream-view.js
import { Readable } from 'stream'
import co from 'koa/node_modules/co'
export default StreamView

// TODO: allow the chunkGenerator to yield objects as well as strings (JSON.stringify them)
class StreamView extends Readable {

  constructor(context, chunkGenerator, options) {
    super({})
    this.chunkGenerator = chunkGenerator
    co.call(this, this.render.bind(this, options)).catch(context.onerror)
  }

  *render(options) {
    for (let chunk of this.chunkGenerator.call(this, options)) {
      this.push(typeof chunk === 'string' ? chunk : yield* chunk)
    }
    this.push(null) // end the stream
  }

  _read() {} // override
}
	import koa from 'koa'
	import router from 'koa-route'
	import streamView from './stream-view'

	const app = koa()
	const toJS = str => JSON.parse(str)
	const toJSON = js => JSON.stringify(js)

	// stream an html page with asynchronous data
	app.use(router.get('/html/:title', streamView('html', function* (title) {
	yield `
	<!DOCTYPE html>
	<html>
	<head>
	<title>${ title }</title>
	<meta charset="utf-8">
	<link rel="stylesheet" href="/bundle.css?${this.request.querystring}" />
	</head>
	<body>
	<div class="mount-node"></div>
	<script type="text/javascript">
	window.props = `; yield getProps(this.request.query); yield `;
	</script>
	<script type="text/javascript" src="bundle.js"></script>
	</body>
	</html>
	`
	})))

	// stream a json file
	// potentially useful for condensing many requests into one
	app.use(router.get('/all-the-things.json', streamView('json', function* (title) {
	yield getProps(this.request.query)
	})))

	function *getProps(queryParams) {
	return toJSON({
	foo: yield fetch(`/some/api`).then(toJS),
	bar: yield fetch(`/some/api/${queryParams.thing}`).then(toJS),
	baz: yield fetch(`/some/api/${queryParams.anotherThing}`).then(toJS)
	})
	}

	app.listen(3000)
	import StreamView from './stream-view'

	export default function getMiddleware(type, chunkGenerator) {
	return function *(options) {
	this.type = type
	this.body = new StreamView(this, chunkGenerator.bind(this), options)
	}
	}
	import { Readable } from 'stream'
	import co from 'koa/node_modules/co'
	export default StreamView

	// TODO: allow the chunkGenerator to yield objects as well as strings (JSON.stringify them)
	class StreamView extends Readable {

	constructor(context, chunkGenerator, options) {
	super({})
	this.chunkGenerator = chunkGenerator
	co.call(this, this.render.bind(this, options)).catch(context.onerror)
	}

	*render(options) {
	for (let chunk of this.chunkGenerator.call(this, options)) {
	this.push(typeof chunk === 'string' ? chunk : yield* chunk)
	}
	this.push(null) // end the stream
	}

	_read() {} // override
	}