bootstrap-pagination.js

// bootstrap-pagination.js

// (c) 2012 Yuku Takahashi
// Freely distributed under the MIT license.

;(function($) {

  'use strict';  // jshint


  // Initial Setup
  // -------------

  var search_obj = {};

  // When `location.search` is '?page=1&query=bootstrap' then `search_obj` is
  // { page: '1', query: 'bootstrap' }.
  (function initialize() {
    var i, length, kv,
        kv_pairs = location.search.substr(1).split('&');
    for (i = 0, length = kv_pairs.length; i < length; i++) {
      kv = kv_pairs[i].split('=');
      if (kv[1]) search_obj[kv[0]] = kv[1];
    }
  })();


  // Pagination Class
  // ----------------

  var Pagination = function(element, options) {

    var i,
        $el = $(element),
        page,   // current page
        last,   // the number of pages
        inner,  // the number of shown pages around current page
        outer;  // the number of shown pages around first and last pages

    this.options = $.extend(true, {}, $.fn.pagination.defaults, options);

    page  = $el.data('page')  || this.options.page ||
            parseInt(search_obj[this.options.key], 10) || 1;
    last  = $el.data('last')  || this.options.last;
    inner = $el.data('inner') || this.options.inner;
    outer = $el.data('outer') || this.options.outer;

    this.$ul = $('<ul></ul>');

    // prev page
    if (this.options.prevlink)
      this.addLink(Math.max(1, page-1), this.options.prevlink, page > 1 ? '' : 'disabled');

    if (outer < page - inner) {
      for (i = 1; i <= outer; i++) this.addLink(i, i);
      if (outer != page - inner - 1) this.addLink(null, '...', 'disabled');
      for (i = page - inner; i < page; i++) this.addLink(i, i);
    } else {
      for (i = 1; i < page; i++) this.addLink(i, i);
    }

    // current page
    this.addLink(page, page, 'active');

    if (page + inner < last - outer + 1) {
      for (i = page + 1; i <= page + inner; i++) this.addLink(i, i);
      if (page + inner != last - outer) this.addLink(null, '...', 'disabled');
      for (i = last - outer + 1; i <= last; i++) this.addLink(i, i);
    } else {
      for (i = page + 1; i <= last; i++) this.addLink(i, i);
    }

    // next page
    if (this.options.nextlink)
      this.addLink(Math.min(last, page+1), this.options.nextlink, page < last ? '' : 'disabled');

    // insert pagination
    this.$ul.appendTo($el);
  };

  Pagination.prototype = {

    constructor: Pagination,

    addLink: function(page, text, className) {
      (className == null) && (className = '');
      $('<li></li>')
        .addClass(className)
        .append(
            $('<a></a>')
              .attr('href', className === 'disabled' ? '#' : this.getHref(page))
              .html(text))
        .appendTo(this.$ul);
    },

    getHref: (function() {
      var base;
      return function(page) {
        var i, length, regexp, kv_pairs, search, qs;
        if (page == null) return '#';
        if (!base) {
          regexp = new RegExp('^' + this.options.key + '=');
          kv_pairs = location.search.substr(1);
          kv_pairs = kv_pairs === '' ? [] : kv_pairs.split('&');
          qs = [];
          for (i = 0, length = kv_pairs.length; i < length; i++) {
            if (!kv_pairs[i].match(regexp)) qs[qs.length] = kv_pairs[i];
          }
          base = location.pathname + '?';
          base += qs.length > 1 ? qs.concat(['']).join('&') : '';
          base += this.options.key + '=';
        }
        return base + page;
      }
    })()
  };


  // Pagination plugin
  // -----------------

  // `options` can have the property which `$.fn.pagination.defaults` has. In
  // addition, it can also have the following properties:
  //
  //   page {Number} The index of current page. If not given, guessed by
  //                 location.search using `key` option or defaults 1.
  //   last {Number} The number of pages.
  $.fn.pagination = function(options) {
    return this.each(function() {
      var $this = $(this), data = $this.data('pagination');
      if (!data) $this.data('pagination', (data = new Pagination(this, options)));
    });
  };

  $.fn.pagination.defaults = {
    key:   'page',        // the name of query stands for current page number
    inner: 2,             // the number of shown pages around current page
    outer: 1,             // the number of shown pages around first and last pages
    prevlink: '&laquo;',  // text of the link to previous page
    nextlink: '&raquo;'   // text of the link to next page
  };
})(jQuery);