flow.js

(function( window ) {

window.Flow = window.Flow || (function() {

	function Flow( slides, params ) {
		var that = this;

		that.params = {
			startPosition: null
		};

		for ( var item in params ) {
			that.params[ item ] = params[ item ];
		}

		if ( typeof slides === 'string' ) {
			that.slides = window.document.querySelectorAll( slides );
		} else {
			that.slides = slides;
		}

		if ( typeof that.params.startPosition === 'number' ) {
			that.show( that.params.startPosition );
		}
	};

	var FlowProto = Flow.prototype;

	FlowProto.show = function( position ) {
		if ( typeof position === "number" && !isNaN( position ) ) {
			return this.movement( this.currentPosition = position );
		} else {
			throw TypeError("Flow.show( position ) - position isn't a number");
		}
	};

	FlowProto.movement = function( position ) {
		var l = this.slides.length,
			i = 0;

		for ( ; i < l; i++ ) {
			this.slides[ i ].style.display = 'none';
		}

		// @TODO: Need to set native display value instead of 'block'
		this.slides[ position ].style.display = 'block';
	};

	// Controllers

	FlowProto.next = function() {
		return this.show( this.currentPosition + 1 === this.size() ? 0 : this.currentPosition + 1 );
	};

	FlowProto.prev = function() {
		return this.show( this.currentPosition === 0 ? this.size() - 1 : this.currentPosition - 1 );
	};

	FlowProto.first = function() {
		return this.show( 0 );
	};

	FlowProto.last = function() {
		return this.show( this.size() - 1 );
	};

	// Secondary

	FlowProto.size = function() {
		return this.slides.length;
	};

	return Flow;

})();

})( this );