You need node-etcd.
$ npm install node-etcd
$ npm install etcd-watcher
var Etcd = require('node-etcd');
var etcd = new Etcd();
var etcdWatcher = require('etcd-watcher');
var watcher = etcdWatcher.watcher(etcd, ['key1', 'key2']);
watcher.wait(function (err, values) {
console.log('keys set', values);
watcher.on('change', function (values) {
console.log('key change', values);
})
});