Differences between AsyncQueue and Deferreds

gistfile1.js

/*
IIRC AsyncQueue is designed for splitting cpu intensive code into chunks and run them sequentially separated by small timeouts.

Deferreds are a way of rewriting async calls without callbacks or events. They are probably more useful in Node.js.

For example, when normally you'd get a lot of callbacks connecting to a db...
*/

mysql_connect('user', 'pwd', function (err) {
	if (err) throw new err;
	mysql_open_database('myDatabase', function (err) {
		if (err) throw new err;
		mysql_query('SELECT * FROM table', function (err, result) {
			if (err) throw new err;
			/* do something */
		});
	});
});

/*
...using a class that uses Deferred you could write: 
*/

var db = new MySQL({
	user: 'user',
	pwd: 'password'
});
db.connect().open('myDatabase').query('SELECT * FROM table').then(function (result) {
	/* do something */
});

/*
With something like this as a MySQL class
 */
var MySQL = Y.Base.create('mysql', Y.Base, [Y.Deferred], {
	
	ATTRS: {
		user: {},
		pwd: {},
		database: {}
	}
	
}, {

	_next: function (promise, err) {
		var args = SLICE.call(arguments, 2);
		if (err) {
			promise.rejectWith(this, args);
		} else {
			promise.resolveWith(this, args);
		}
	},

	connect: function () {
		return this.promise(function (p) {
			mysql_connect(this.get('user'), this.get('pwd'), Y.bind(this._next, this, p));
		});
	},
	
	open: function (db) {
		return this.promise(function (p) {
			mysql_open_database(db || this.get('database'), Y.bind(this._next, this, p));
		});
	},
	
	query: function (query) {
		return this.promise(function (p) {
			mysql_query(query, Y.bind(this._next, this, p));
		});
	}
	
});