jquery/src/queue.js

(function( jQuery ) {

jQuery.extend({
	queue: function( elem, type, data ) {
		if ( !elem ) {
			return;
		}

		type = (type || "fx") + "queue";
		var q = jQuery._data( elem, type );

		// Speed up dequeue by getting out quickly if this is just a lookup
		if ( !data ) {
			return q || [];
		}

		if ( !q || jQuery.isArray(data) ) {
			q = jQuery._data( elem, type, jQuery.makeArray(data) );

		} else {
			q.push( data );
		}

		return q;
	},

	dequeue: function( elem, type ) {
		type = type || "fx";

		var queue = jQuery.queue( elem, type ),
			fn = queue.shift(),
			defer;

		// If the fx queue is dequeued, always remove the progress sentinel
		if ( fn === "inprogress" ) {
			fn = queue.shift();
		}

		if ( fn ) {
			// Add a progress sentinel to prevent the fx queue from being
			// automatically dequeued
			if ( type === "fx" ) {
				queue.unshift("inprogress");
			}

			fn.call(elem, function() {
				jQuery.dequeue(elem, type);
			});
		}

		if ( !queue.length ) {
			jQuery.removeData( elem, type + "queue", true );
			// Look if we have observers and resolve if needed
			if (( defer = jQuery.data( elem, type + "defer", undefined, true ) )) {
				// Give room for hard-coded callbacks to fire first
				// and eventually add another animation on the element
				setTimeout( function() {
					if ( !jQuery.data( elem, type + "queue", undefined, true ) ) {
						jQuery.removeData( elem, type + "defer", true );
						defer.resolve();
					}
				}, 0 );
			}
		}
	}
});

jQuery.fn.extend({
	queue: function( type, data ) {
		if ( typeof type !== "string" ) {
			data = type;
			type = "fx";
		}

		if ( data === undefined ) {
			return jQuery.queue( this[0], type );
		}
		return this.each(function( i ) {
			var queue = jQuery.queue( this, type, data );

			if ( type === "fx" && queue[0] !== "inprogress" ) {
				jQuery.dequeue( this, type );
			}
		});
	},
	dequeue: function( type ) {
		return this.each(function() {
			jQuery.dequeue( this, type );
		});
	},

	// Based off of the plugin by Clint Helfers, with permission.
	// http://blindsignals.com/index.php/2009/07/jquery-delay/
	delay: function( time, type ) {
		time = jQuery.fx ? jQuery.fx.speeds[time] || time : time;
		type = type || "fx";

		return this.queue( type, function() {
			var elem = this;
			setTimeout(function() {
				jQuery.dequeue( elem, type );
			}, time );
		});
	},

	clearQueue: function( type ) {
		return this.queue( type || "fx", [] );
	},

	// Get a promise resolved when queues of a certain type
	// are emptied (fx is the type by default)
	promise: function( type, object ) {
		if ( typeof type !== "string" ) {
			object = type;
			type = undefined;
		}
		type = type || "fx";
		var defer = jQuery.Deferred(),
			elements = this,
			i = elements.length,
			count = 1,
			deferDataKey = type + "defer",
			queueDataKey = type + "queue";
		function resolve() {
			if ( !( --count ) ) {
				defer.resolveWith( elements, [ elements ] );
			}
		}
		while( i-- ) {
			if (( tmp = jQuery.data( elements[ i ], deferDataKey, undefined, true ) ||
					jQuery.data( elements[ i ], queueDataKey, undefined, true ) &&
					jQuery.data( elements[ i ], deferDataKey, jQuery._Deferred(), true ) )) {
				count++;
				tmp.done( resolve );
			}
		}
		resolve();
		return defer.promise();
	}
});

})( jQuery );