steal-tools/lib/stream/live.js

Futuristic build tools for ES6 Module applications.

var watch = require("./watch");
var createBundleGraphStream = require("../graph/make_graph_with_bundles").createBundleGraphStream;
var recycle = require("../graph/recycle");
var createServer = require("../create_websocket_server");
var defaults = require("lodash").defaults;
var logging = require("../logger");
var toPromise = require("./to_promise");

module.exports = function(config, options){
	if(!options) options = {};
	defaults(options, { quiet: true });
	logging.setup(options, config);
	options.localStealConfig = {
		env: "build-development"
	};

	// Create an initial dependency graph for this config.
	var initialGraphStream = createBundleGraphStream(config, options);
	// Create a stream that is used to regenerate a new graph on file changes.
	var graphStream = recycle(config, options);
	var graphPromise = toPromise(graphStream);

	// Pipe the graph stream into the recycleStream so it can get the initial
	// graph.
	initialGraphStream.pipe(graphStream);

	// Setup the websocket connection.
	var wss = createServer(options);
	var port = wss.options.server.address().port;

	wss.on("connection", function(ws){
		// Get the initial graph for this main,
		// if it's not already part of the graph.
		ws.once("message", function(moduleName){
			graphPromise.then(function(){
				graphStream.write(moduleName);
			});
		});
	});

	var watchStream = watch(graphStream);
	watchStream.on("data", onChange);

	function onChange(node) {
		var moduleName = node ? node.load.name : "";

		if(moduleName) {
			console.error("Reloading", moduleName.green);

			// Alert all clients of the change
			wss.clients.forEach(function(ws){
				ws.send(moduleName);
			});
		}

		// Update our dependency graph
		graphStream.write(moduleName);
	}

	graphStream.once("data", function(){
		console.error("Live-reload server listening on port", port);
	});

	graphStream.on("error", function(err){
		if(err.moduleName) {
			console.error("Oops! Error reloading", err.moduleName.red);
		} else {
			console.error(err);
		}
	});

	initialGraphStream.write(config.main);

	return graphStream;
};