pdfjs/web/viewer.js
function PDFOutlineViewer_addToggleButton(div) {
            var toggler = document.createElement('div');
            toggler.className = 'outlineItemToggler';
            toggler.onclick = function (event) {
              event.stopPropagation();
              toggler.classList.toggle('outlineItemsHidden');
              if (event.shiftKey) {
                var shouldShowAll = !toggler.classList.contains('outlineItemsHidden');
                this._toggleOutlineItem(div, shouldShowAll);
              }
            }.bind(this);
            div.insertBefore(toggler, div.firstChild);
          }
function PDFOutlineViewer_addToggleButton(div) {
            var toggler = document.createElement('div');
            toggler.className = 'outlineItemToggler';
            toggler.onclick = function (event) {
              event.stopPropagation();
              toggler.classList.toggle('outlineItemsHidden');
              if (event.shiftKey) {
                var shouldShowAll = !toggler.classList.contains('outlineItemsHidden');
                this._toggleOutlineItem(div, shouldShowAll);
              }
            }.bind(this);
            div.insertBefore(toggler, div.firstChild);
          }
function PDFOutlineViewer_addToggleButton ( div ) { var toggler = document . createElement ( 'div' ) ; toggler . className = 'outlineItemToggler' ; toggler . onclick = function ( event ) { event . stopPropagation ( ) ; toggler . classList . toggle ( 'outlineItemsHidden' ) ; if ( event . shiftKey ) { var shouldShowAll = ! toggler . classList . contains ( 'outlineItemsHidden' ) ; this . _toggleOutlineItem ( div , shouldShowAll ) ; } } . bind ( this ) ; div . insertBefore ( toggler , div . firstChild ) ; }
Prepend a button before an outline item which allows the user to toggle
the visibility of all outline items at that level.

@private
Prepend a button before an outline item which allows the user to toggle the visibility of all outline items at that level .