client.js

var elasticsearch = require('elasticsearch')
var client = new elasticsearch.Client({
    host: 'localhost:9200',
    log: 'trace'
});

client.ping({
    requestTimeout:30000,
    hello:"elasticsearch"
}, function(error) {
    if (error) {
	console.error('elasticsearch cluster is down!');
	} else {
	    console.log("All is well");
	}
});