File: paginator/js/paginator-core.js

            /**
             Paginator's core functionality consists of keeping track of the current page
             being displayed and providing information for previous and next pages.
            
             @module paginator
             @submodule paginator-core
             @since 3.11.0
             */
            
            /**
             _API docs for this extension are included in the Paginator class._
            
             Class extension providing the core API and structure for the Paginator module.
            
             Use this class extension with Widget or another Base-based superclass to
             create the basic Paginator model API and composing class structure.
            
             @class Paginator.Core
             @for Paginator
             @since 3.11.0
             */
            
            var PaginatorCore = Y.namespace('Paginator').Core = function () {};
            
            PaginatorCore.ATTRS = {
                /**
                 Current page count. First page is 1.
            
                 @attribute page
                 @type Number
                 @default 1
                 **/
                page: {
                    value: 1
                },
            
                /**
                 Total number of pages to display
            
                 @readOnly
                 @attribute totalPages
                 @type Number
                 **/
                totalPages: {
                    readOnly: true,
                    getter: '_getTotalPagesFn'
                },
            
                /**
                 Maximum number of items per page. A value of negative one (-1) indicates
                     all items on one page.
            
                 @attribute itemsPerPage
                 @type Number
                 @default 10
                 **/
                itemsPerPage: {
                    value: 10
                },
            
                /**
                 Total number of items in all pages.
            
                 @attribute totalItems
                 @type Number
                 @default 0
                 **/
                totalItems: {
                    value: 0
                }
            };
            
            Y.mix(PaginatorCore.prototype, {
                /**
                 Sets the page to the previous page in the set, if there is a previous page.
                 @method prevPage
                 @chainable
                 */
                prevPage: function () {
                    if (this.hasPrevPage()) {
                        this.set('page', this.get('page') - 1);
                    }
            
                    return this;
                },
            
                /**
                 Sets the page to the next page in the set, if there is a next page.
            
                 @method nextPage
                 @chainable
                 */
                nextPage: function () {
                    if (this.hasNextPage()) {
                        this.set('page', this.get('page') + 1);
                    }
            
                    return this;
                },
            
                /**
                 Returns True if there is a previous page in the set.
            
                 @method hasPrevPage
                 @return {Boolean} `true` if there is a previous page, `false` otherwise.
                 */
                hasPrevPage: function () {
                    return this.get('page') > 1;
                },
            
                /**
                 Returns True if there is a next page in the set.
            
                 If totalItems isn't set, assume there is always next page.
            
                 @method hasNextPage
                 @return {Boolean} `true` if there is a next page, `false` otherwise.
                 */
                hasNextPage: function () {
                    return (!this.get('totalItems') || this.get('page') < this.get('totalPages'));
                },
            
            
                //--- P R O T E C T E D
            
                /**
                 Returns the total number of pages based on the total number of
                   items provided and the number of items per page
            
                 @protected
                 @method _getTotalPagesFn
                 @return {Number} Total number of pages based on total number of items and
                   items per page or one if itemsPerPage is less than one
                 */
                _getTotalPagesFn: function () {
                    var itemsPerPage = this.get('itemsPerPage');
            
                    return (itemsPerPage < 1) ? 1 : Math.ceil(this.get('totalItems') / itemsPerPage);
                }
            });