tabs.js

(function ($) {

  var methods = {
    init : function(options) {
      var defaults = {
        onShow: null,
        swipeable: false,
        responsiveThreshold: Infinity, // breakpoint for swipeable
      };
      options = $.extend(defaults, options);
      var namespace = Materialize.objectSelectorString($(this));

      return this.each(function(i) {

      var uniqueNamespace = namespace+i;

      // For each set of tabs, we want to keep track of
      // which tab is active and its associated content
      var $this = $(this),
          window_width = $(window).width();

      var $active, $content, $links = $this.find('li.tab a'),
          $tabs_width = $this.width(),
          $tabs_content = $(),
          $tabs_wrapper,
          $tab_width = Math.max($tabs_width, $this[0].scrollWidth) / $links.length,
          $indicator,
          index = prev_index = 0,
          clicked = false,
          clickedTimeout,
          transition = 300;


      // Finds right attribute for indicator based on active tab.
      // el: jQuery Object
        var calcRightPos = function(el) {
          return Math.ceil($tabs_width - el.position().left - el[0].getBoundingClientRect().width - $this.scrollLeft());
      };

      // Finds left attribute for indicator based on active tab.
      // el: jQuery Object
      var calcLeftPos = function(el) {
        return Math.floor(el.position().left + $this.scrollLeft());
      };

      // Animates Indicator to active tab.
      // prev_index: Number
      var animateIndicator = function(prev_index) {
        if ((index - prev_index) >= 0) {
          $indicator.velocity({"right": calcRightPos($active) }, { duration: transition, queue: false, easing: 'easeOutQuad'});
          $indicator.velocity({"left": calcLeftPos($active) }, {duration: transition, queue: false, easing: 'easeOutQuad', delay: 90});

        } else {
          $indicator.velocity({"left": calcLeftPos($active) }, { duration: transition, queue: false, easing: 'easeOutQuad'});
          $indicator.velocity({"right": calcRightPos($active) }, {duration: transition, queue: false, easing: 'easeOutQuad', delay: 90});
        }
      };

      // Change swipeable according to responsive threshold
      if (options.swipeable) {
        if (window_width > options.responsiveThreshold) {
          options.swipeable = false;
        }
      }


      // If the location.hash matches one of the links, use that as the active tab.
      $active = $($links.filter('[href="'+location.hash+'"]'));

      // If no match is found, use the first link or any with class 'active' as the initial active tab.
      if ($active.length === 0) {
        $active = $(this).find('li.tab a.active').first();
      }
      if ($active.length === 0) {
        $active = $(this).find('li.tab a').first();
      }

      $active.addClass('active');
      index = $links.index($active);
      if (index < 0) {
        index = 0;
      }

      if ($active[0] !== undefined) {
        $content = $($active[0].hash);
        $content.addClass('active');
      }

      // append indicator then set indicator width to tab width
      if (!$this.find('.indicator').length) {
        $this.append('<li class="indicator"></li>');
      }
      $indicator = $this.find('.indicator');

      // we make sure that the indicator is at the end of the tabs
      $this.append($indicator);

      if ($this.is(":visible")) {
        // $indicator.css({"right": $tabs_width - ((index + 1) * $tab_width)});
        // $indicator.css({"left": index * $tab_width});
        setTimeout(function() {
          $indicator.css({"right": calcRightPos($active) });
          $indicator.css({"left": calcLeftPos($active) });
        }, 0);
      }
      $(window).off('resize.tabs-'+uniqueNamespace).on('resize.tabs-'+uniqueNamespace, function () {
        $tabs_width = $this.width();
        $tab_width = Math.max($tabs_width, $this[0].scrollWidth) / $links.length;
        if (index < 0) {
          index = 0;
        }
        if ($tab_width !== 0 && $tabs_width !== 0) {
          $indicator.css({"right": calcRightPos($active) });
          $indicator.css({"left": calcLeftPos($active) });
        }
      });

      // Initialize Tabs Content.
      if (options.swipeable) {
        // TODO: Duplicate calls with swipeable? handle multiple div wrapping.
        $links.each(function () {
          var $curr_content = $(Materialize.escapeHash(this.hash));
          $curr_content.addClass('carousel-item');
          $tabs_content = $tabs_content.add($curr_content);
        });
        $tabs_wrapper = $tabs_content.wrapAll('<div class="tabs-content carousel"></div>');
        $tabs_content.css('display', '');
        $('.tabs-content.carousel').carousel({
          fullWidth: true,
          noWrap: true,
          onCycleTo: function(item) {
            if (!clicked) {
              var prev_index = index;
              index = $tabs_wrapper.index(item);
              $active.removeClass('active');
              $active = $links.eq(index);
              $active.addClass('active');
              animateIndicator(prev_index);
              if (typeof(options.onShow) === "function") {
                options.onShow.call($this[0], $content);
              }
            }
          },
        });
      } else {
        // Hide the remaining content
        $links.not($active).each(function () {
          $(Materialize.escapeHash(this.hash)).hide();
        });
      }


      // Bind the click event handler
      $this.off('click.tabs').on('click.tabs', 'a', function(e) {
        if ($(this).parent().hasClass('disabled')) {
          e.preventDefault();
          return;
        }

        // Act as regular link if target attribute is specified.
        if (!!$(this).attr("target")) {
          return;
        }

        clicked = true;
        $tabs_width = $this.width();
        $tab_width = Math.max($tabs_width, $this[0].scrollWidth) / $links.length;

        // Make the old tab inactive.
        $active.removeClass('active');
        var $oldContent = $content

        // Update the variables with the new link and content
        $active = $(this);
        $content = $(Materialize.escapeHash(this.hash));
        $links = $this.find('li.tab a');
        var activeRect = $active.position();

        // Make the tab active.
        $active.addClass('active');
        prev_index = index;
        index = $links.index($(this));
        if (index < 0) {
          index = 0;
        }
        // Change url to current tab
        // window.location.hash = $active.attr('href');

        // Swap content
        if (options.swipeable) {
          if ($tabs_content.length) {
            $tabs_content.carousel('set', index, function() {
              if (typeof(options.onShow) === "function") {
                options.onShow.call($this[0], $content);
              }
            });
          }
        } else {
          if ($content !== undefined) {
            $content.show();
            $content.addClass('active');
            if (typeof(options.onShow) === "function") {
              options.onShow.call(this, $content);
            }
          }

          if ($oldContent !== undefined &&
              !$oldContent.is($content)) {
            $oldContent.hide();
            $oldContent.removeClass('active');
          }
        }

        // Reset clicked state
        clickedTimeout = setTimeout(function(){ clicked = false; }, transition);

        // Update indicator
        animateIndicator(prev_index);

        // Prevent the anchor's default click action
        e.preventDefault();
      });
    });

    },
    select_tab : function( id ) {
      this.find('a[href="#' + id + '"]').trigger('click');
    }
  };

  $.fn.tabs = function(methodOrOptions) {
    if ( methods[methodOrOptions] ) {
      return methods[ methodOrOptions ].apply( this, Array.prototype.slice.call( arguments, 1 ));
    } else if ( typeof methodOrOptions === 'object' || ! methodOrOptions ) {
      // Default to "init"
      return methods.init.apply( this, arguments );
    } else {
      $.error( 'Method ' +  methodOrOptions + ' does not exist on jQuery.tabs' );
    }
  };

  $(document).ready(function(){
    $('ul.tabs').tabs();
  });
}( jQuery ));