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Understanding Trigger in Jquery

Hi,

I am using AdminLTE Dashboard Template to build my portal. In the Javascript file I came across the trigger function. Below is the part of the jquery code.

Kindly help me understand how the trigger function works in below code.

$.AdminLTE.pushMenu = {
    activate: function (toggleBtn) {
      //Get the screen sizes
      var screenSizes = $.AdminLTE.options.screenSizes;

      //Enable sidebar toggle
      $(document).on('click', toggleBtn, function (e) {
        e.preventDefault();

        //Enable sidebar push menu
        if ($(window).width() > (screenSizes.sm - 1)) {
          if ($("body").hasClass('sidebar-collapse')) {
            $("body").removeClass('sidebar-collapse').trigger('expanded.pushMenu');
          } else {
            $("body").addClass('sidebar-collapse').trigger('collapsed.pushMenu');
          }
        }
        //Handle sidebar push menu for small screens
        else {
          if ($("body").hasClass('sidebar-open')) {
            $("body").removeClass('sidebar-open').removeClass('sidebar-collapse').trigger('collapsed.pushMenu');
          } else {
            $("body").addClass('sidebar-open').trigger('expanded.pushMenu');
          }
        }
      });

      $(".content-wrapper").click(function () {
        //Enable hide menu when clicking on the content-wrapper on small screens
        if ($(window).width() <= (screenSizes.sm - 1) && $("body").hasClass("sidebar-open")) {
          $("body").removeClass('sidebar-open');
        }
      });

      //Enable expand on hover for sidebar mini
      if ($.AdminLTE.options.sidebarExpandOnHover
        || ($('body').hasClass('fixed')
        && $('body').hasClass('sidebar-mini'))) {
        this.expandOnHover();
      }
    },
    expandOnHover: function () {
      var _this = this;
      var screenWidth = $.AdminLTE.options.screenSizes.sm - 1;
      //Expand sidebar on hover
      $('.main-sidebar').hover(function () {
        if ($('body').hasClass('sidebar-mini')
          && $("body").hasClass('sidebar-collapse')
          && $(window).width() > screenWidth) {
          _this.expand();
        }
      }, function () {
        if ($('body').hasClass('sidebar-mini')
          && $('body').hasClass('sidebar-expanded-on-hover')
          && $(window).width() > screenWidth) {
          _this.collapse();
        }
      });
    },
    expand: function () {
      $("body").removeClass('sidebar-collapse').addClass('sidebar-expanded-on-hover');
    },
    collapse: function () {
      if ($('body').hasClass('sidebar-expanded-on-hover')) {
        $('body').removeClass('sidebar-expanded-on-hover').addClass('sidebar-collapse');
      }
    }
  };

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Thanks in advance.

James Bilous

Triggered is a jQuery function that simply emulates an event taking place. These events are any that you can respond to using jQuery, such as "click", "keydown", or in your case "expanded" and "collapsed.

The code you have posted is using trigger to expand and collapse menus in response to the window being resized. This is because normally a window resize does not trigger these events. They are probably doing this to facilitate the responsiveness of the layout.

Vipin Kumar

ASKER

@James,

Can you please elaborate on this trigger trigger('expanded.pushMenu'). I dont see any where in my code expanded written, what I see only is expand: function (). Then how does it understand expanded.

Thanks in advance.

ASKER CERTIFIED SOLUTION

James Bilous

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Vipin Kumar

ASKER

@James,

I have searched all the files, there is no where I find that expanded is defined. That is why I am getting confused.

SOLUTION

James Bilous

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James Bilous

I found this pull request for a code change on AdminLTE. You can see them discussing "expanded.pushMenu" as an event they added so people can respond to the menu changing in their own code:

https://github.com/almasaeed2010/AdminLTE/issues/444

Vipin Kumar

ASKER

@James,

Then you mean that this code is not being executed at all.

James Bilous

Correct, that's what I mean.

Vipin Kumar

ASKER

@James,

Just last question, the whole code is not executed i.e. $("body").removeClass('sidebar-collapse').trigger('expanded.pushMenu'); or only the trigger is not executed.

SOLUTION

James Bilous

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