Update README.md

README.md

@@ -22,6 +22,28 @@ connection.when('available', function (err, db) {
 });
 ```
 
+## Heartbeat
+
+Heartbeat is useful, when you want check connection from time to time. For example, if you working with mongodb and cache connection to db - what happens when server, which connection binded to goes to heaven? Connection is lost and programmer should recreate it.
+
+__Note:__ for now there is no way to stop heartbeats.
+
+```js
+var connectOnce = require('connect-once');
+
+var connection = new connectOnce({ 
+    heartbeat: function (db, beat) {
+        db.stats(function (err) {
+            if (!err) { beat(); }
+        });
+    }
+}, MongoClient.connect, 'mongodb://localhost/test');
+
+connection.when('available', function (err, db) {
+    // Do stuff
+});
+```
+
 ## API
 
 Read the [documentation of Connection class](http://floatdrop.github.io/connect-once/Connection.html). 

index.js

@@ -1,7 +1,5 @@
 'use strict';
 
-var async = require('async');
-
 /**
  * Creates event emitter, which will pass connection to listeners,
  * when connect function callback will be called.
@@ -89,6 +87,11 @@ Connection.prototype.retry = function retry() {
     }.bind(this), this.options.reconnectWait);
 };
 
+/**
+ * This method starts checking connection with heartbeat function.
+ *
+ * @method
+ */
 Connection.prototype.checkPulse = function checkPulse(args) {
     var timer = setTimeout(function () {
         this.retry(new Error('Connection is dead'));

package.json

@@ -27,8 +27,5 @@
   "bugs": {
     "url": "https://github.com/floatdrop/connect-once/issues"
   },
-  "homepage": "https://github.com/floatdrop/connect-once",
-  "dependencies": {
-    "async": "~0.2.10"
-  }
+  "homepage": "https://github.com/floatdrop/connect-once"
 }