example of implementing a file watcher with an http endpoint for client.js to poll for reloads

client.js

function checkForReload() {
    var xhr = new XMLHttpRequest
    xhr.open('get', 'http://localhost:1978', true)
    xhr.setRequestHeader('X-Requested-With','XMLHttpRequest')
    xhr.onreadystatechange = function() {
        if (this.readyState === 4 && /^[20]/.test(this.status)) {
            var reload = JSON.parse(this.responseText).reload
            if (reload) window.location.reload()
        }
    }
    xhr.send()
}

setInterval(checkForReload, 1000*5)

server.js

var Gaze    = require('gaze').Gaze
  , watches = ['www/*', 'test/*']
  , watch   = new Gaze(watches)
  , http    = require('http')
  , reload  = false

watch.on('ready', function(watcher) {
    console.log('Watching ', watches)
})

watch.on('all', function(event, filepath) {
    reload = true
    console.log(event, filepath, ' sending reload')
})

function reloader(req, res) {
    res.writeHead(200, {'Content-Type':'text/json'})
    res.end(JSON.stringify({reload:reload}))
    // reset reload
    console.log('Reload requested')
    reload = false
}

http.createServer(reloader).listen(1978, function() {
    console.log('Watch server on http://localhost:1978')
})

why poll? just have the server not return anything until the watch trips; then the client reloads when the get returns anything; maybe you'll need to dribble out a byte or so every 30 seconds or so to keep the browser from closing the XHR?

I'd actually use something like this, but in my case, when my "code" changes, I kill the server and relaunch it; same client code waiting for the "end" of the response might just work there too, but I'm a little worried the port might go into a zombie state with the browser request being open ...

Keep in mind that there is a huge watch delay on Mac OS X. I've seen it be over a minute. Nothing you can do about it, it's their awful fs and kernel :(

Quick tip: Use setTimeout recursively instead setInterval. Browsers are stopping setIntervals in unfocused tabs/windows