Convert presentation mode to ES6 syntax

web/pdf_presentation_mode.js

@@ -15,10 +15,19 @@
 
 import { normalizeWheelEventDelta } from './ui_utils';
 
-var DELAY_BEFORE_RESETTING_SWITCH_IN_PROGRESS = 1500; // in ms
-var DELAY_BEFORE_HIDING_CONTROLS = 3000; // in ms
-var ACTIVE_SELECTOR = 'pdfPresentationMode';
-var CONTROLS_SELECTOR = 'pdfPresentationModeControls';
+const DELAY_BEFORE_RESETTING_SWITCH_IN_PROGRESS = 1500; // in ms
+const DELAY_BEFORE_HIDING_CONTROLS = 3000; // in ms
+const ACTIVE_SELECTOR = 'pdfPresentationMode';
+const CONTROLS_SELECTOR = 'pdfPresentationModeControls';
+const MOUSE_SCROLL_COOLDOWN_TIME = 50; // in ms
+const PAGE_SWITCH_THRESHOLD = 0.1;
+
+// Number of CSS pixels for a movement to count as a swipe.
+const SWIPE_MIN_DISTANCE_THRESHOLD = 50;
+
+// Swipe angle deviation from the x or y axis before it is not
+// considered a swipe in that direction any more.
+const SWIPE_ANGLE_THRESHOLD = Math.PI / 6;
 
 /**
  * @typedef {Object} PDFPresentationModeOptions
@@ -30,15 +39,11 @@ var CONTROLS_SELECTOR = 'pdfPresentationModeControls';
  *   to the context menu in Presentation Mode.
  */
 
+class PDFPresentationMode {
   /**
- * @class
- */
-var PDFPresentationMode = (function PDFPresentationModeClosure() {
-  /**
-   * @constructs PDFPresentationMode
    * @param {PDFPresentationModeOptions} options
    */
-  function PDFPresentationMode(options) {
+  constructor(options) {
     this.container = options.container;
     this.viewer = options.viewer || options.container.firstElementChild;
     this.pdfViewer = options.pdfViewer;
@@ -53,37 +58,31 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
     this.touchSwipeState = null;
 
     if (contextMenuItems) {
-      contextMenuItems.contextFirstPage.addEventListener('click',
-          function PDFPresentationMode_contextFirstPageClick(e) {
+      contextMenuItems.contextFirstPage.addEventListener('click', () => {
         this.contextMenuOpen = false;
         this.eventBus.dispatch('firstpage');
-      }.bind(this));
-      contextMenuItems.contextLastPage.addEventListener('click',
-          function PDFPresentationMode_contextLastPageClick(e) {
+      });
+      contextMenuItems.contextLastPage.addEventListener('click', () => {
         this.contextMenuOpen = false;
         this.eventBus.dispatch('lastpage');
-      }.bind(this));
-      contextMenuItems.contextPageRotateCw.addEventListener('click',
-          function PDFPresentationMode_contextPageRotateCwClick(e) {
+      });
+      contextMenuItems.contextPageRotateCw.addEventListener('click', () => {
         this.contextMenuOpen = false;
         this.eventBus.dispatch('rotatecw');
-      }.bind(this));
-      contextMenuItems.contextPageRotateCcw.addEventListener('click',
-          function PDFPresentationMode_contextPageRotateCcwClick(e) {
+      });
+      contextMenuItems.contextPageRotateCcw.addEventListener('click', () => {
         this.contextMenuOpen = false;
         this.eventBus.dispatch('rotateccw');
-      }.bind(this));
+      });
     }
   }
 
-  PDFPresentationMode.prototype = {
   /**
    * Request the browser to enter fullscreen mode.
    * @returns {boolean} Indicating if the request was successful.
    */
-    request: function PDFPresentationMode_request() {
-      if (this.switchInProgress || this.active ||
-          !this.viewer.hasChildNodes()) {
+  request() {
+    if (this.switchInProgress || this.active || !this.viewer.hasChildNodes()) {
       return false;
     }
     this._addFullscreenChangeListeners();
@@ -108,12 +107,12 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
     };
 
     return true;
-    },
+  }
 
   /**
    * @private
    */
-    _mouseWheel: function PDFPresentationMode_mouseWheel(evt) {
+  _mouseWheel(evt) {
     if (!this.active) {
       return;
     }
@@ -121,10 +120,6 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
     evt.preventDefault();
 
     var delta = normalizeWheelEventDelta(evt);
-
-      var MOUSE_SCROLL_COOLDOWN_TIME = 50;
-      var PAGE_SWITCH_THRESHOLD = 0.1;
-
     var currentTime = (new Date()).getTime();
     var storedTime = this.mouseScrollTimeStamp;
 
@@ -149,19 +144,17 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
         this.mouseScrollTimeStamp = currentTime;
       }
     }
-    },
+  }
 
   get isFullscreen() {
-      return !!(document.fullscreenElement ||
-                document.mozFullScreen ||
-                document.webkitIsFullScreen ||
-                document.msFullscreenElement);
-    },
+    return !!(document.fullscreenElement || document.mozFullScreen ||
+              document.webkitIsFullScreen || document.msFullscreenElement);
+  }
 
   /**
    * @private
    */
-    _goToPreviousPage: function PDFPresentationMode_goToPreviousPage() {
+  _goToPreviousPage() {
     var page = this.pdfViewer.currentPageNumber;
     // If we're at the first page, we don't need to do anything.
     if (page <= 1) {
@@ -169,12 +162,12 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
     }
     this.pdfViewer.currentPageNumber = (page - 1);
     return true;
-    },
+  }
 
   /**
    * @private
    */
-    _goToNextPage: function PDFPresentationMode_goToNextPage() {
+  _goToNextPage() {
     var page = this.pdfViewer.currentPageNumber;
     // If we're at the last page, we don't need to do anything.
     if (page >= this.pdfViewer.pagesCount) {
@@ -182,18 +175,18 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
     }
     this.pdfViewer.currentPageNumber = (page + 1);
     return true;
-    },
+  }
 
   /**
    * @private
    */
-    _notifyStateChange: function PDFPresentationMode_notifyStateChange() {
+  _notifyStateChange() {
     this.eventBus.dispatch('presentationmodechanged', {
       source: this,
       active: this.active,
-        switchInProgress: !!this.switchInProgress
+      switchInProgress: !!this.switchInProgress,
     });
-    },
+  }
 
   /**
    * Used to initialize a timeout when requesting Presentation Mode,
@@ -201,34 +194,34 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
    * This timeout is used to prevent the current page from being scrolled
    * partially, or completely, out of view when entering Presentation Mode.
    * NOTE: This issue seems limited to certain zoom levels (e.g. page-width).
+   *
    * @private
    */
-    _setSwitchInProgress: function PDFPresentationMode_setSwitchInProgress() {
+  _setSwitchInProgress() {
     if (this.switchInProgress) {
       clearTimeout(this.switchInProgress);
     }
-      this.switchInProgress = setTimeout(function switchInProgressTimeout() {
+    this.switchInProgress = setTimeout(() => {
       this._removeFullscreenChangeListeners();
       delete this.switchInProgress;
       this._notifyStateChange();
-      }.bind(this), DELAY_BEFORE_RESETTING_SWITCH_IN_PROGRESS);
-    },
+    }, DELAY_BEFORE_RESETTING_SWITCH_IN_PROGRESS);
+  }
 
   /**
    * @private
    */
-    _resetSwitchInProgress:
-        function PDFPresentationMode_resetSwitchInProgress() {
+  _resetSwitchInProgress() {
     if (this.switchInProgress) {
       clearTimeout(this.switchInProgress);
       delete this.switchInProgress;
     }
-    },
+  }
 
   /**
    * @private
    */
-    _enter: function PDFPresentationMode_enter() {
+  _enter() {
     this.active = true;
     this._resetSwitchInProgress();
     this._notifyStateChange();
@@ -236,10 +229,10 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
 
     // Ensure that the correct page is scrolled into view when entering
     // Presentation Mode, by waiting until fullscreen mode in enabled.
-      setTimeout(function enterPresentationModeTimeout() {
+    setTimeout(() => {
       this.pdfViewer.currentPageNumber = this.args.page;
       this.pdfViewer.currentScaleValue = 'page-fit';
-      }.bind(this), 0);
+    }, 0);
 
     this._addWindowListeners();
     this._showControls();
@@ -250,18 +243,18 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
     // for the user to deselect text that is selected (e.g. with "Select all")
     // when entering Presentation Mode, hence we remove any active selection.
     window.getSelection().removeAllRanges();
-    },
+  }
 
   /**
    * @private
    */
-    _exit: function PDFPresentationMode_exit() {
+  _exit() {
     var page = this.pdfViewer.currentPageNumber;
     this.container.classList.remove(ACTIVE_SELECTOR);
 
     // Ensure that the correct page is scrolled into view when exiting
     // Presentation Mode, by waiting until fullscreen mode is disabled.
-      setTimeout(function exitPresentationModeTimeout() {
+    setTimeout(() => {
       this.active = false;
       this._removeFullscreenChangeListeners();
       this._notifyStateChange();
@@ -269,27 +262,27 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
       this.pdfViewer.currentScaleValue = this.args.previousScale;
       this.pdfViewer.currentPageNumber = page;
       this.args = null;
-      }.bind(this), 0);
+    }, 0);
 
     this._removeWindowListeners();
     this._hideControls();
     this._resetMouseScrollState();
     this.container.removeAttribute('contextmenu');
     this.contextMenuOpen = false;
-    },
+  }
 
   /**
    * @private
    */
-    _mouseDown: function PDFPresentationMode_mouseDown(evt) {
+  _mouseDown(evt) {
     if (this.contextMenuOpen) {
       this.contextMenuOpen = false;
       evt.preventDefault();
       return;
     }
     if (evt.button === 0) {
-        // Enable clicking of links in presentation mode. Please note:
-        // Only links pointing to destinations in the current PDF document work.
+      // Enable clicking of links in presentation mode. Note: only links
+      // pointing to destinations in the current PDF document work.
       var isInternalLink = (evt.target.href &&
                             evt.target.classList.contains('internalLink'));
       if (!isInternalLink) {
@@ -298,78 +291,72 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
         this.pdfViewer.currentPageNumber += (evt.shiftKey ? -1 : 1);
       }
     }
-    },
+  }
 
   /**
    * @private
    */
-    _contextMenu: function PDFPresentationMode_contextMenu() {
+  _contextMenu() {
     this.contextMenuOpen = true;
-    },
+  }
 
   /**
    * @private
    */
-    _showControls: function PDFPresentationMode_showControls() {
+  _showControls() {
     if (this.controlsTimeout) {
       clearTimeout(this.controlsTimeout);
     } else {
       this.container.classList.add(CONTROLS_SELECTOR);
     }
-      this.controlsTimeout = setTimeout(function showControlsTimeout() {
+    this.controlsTimeout = setTimeout(() => {
       this.container.classList.remove(CONTROLS_SELECTOR);
       delete this.controlsTimeout;
-      }.bind(this), DELAY_BEFORE_HIDING_CONTROLS);
-    },
+    }, DELAY_BEFORE_HIDING_CONTROLS);
+  }
 
   /**
    * @private
    */
-    _hideControls: function PDFPresentationMode_hideControls() {
+  _hideControls() {
     if (!this.controlsTimeout) {
       return;
     }
     clearTimeout(this.controlsTimeout);
     this.container.classList.remove(CONTROLS_SELECTOR);
     delete this.controlsTimeout;
-    },
+  }
 
   /**
    * Resets the properties used for tracking mouse scrolling events.
+   *
    * @private
    */
-    _resetMouseScrollState:
-        function PDFPresentationMode_resetMouseScrollState() {
+  _resetMouseScrollState() {
     this.mouseScrollTimeStamp = 0;
     this.mouseScrollDelta = 0;
-    },
+  }
 
   /**
    * @private
    */
-    _touchSwipe: function PDFPresentationMode_touchSwipe(evt) {
+  _touchSwipe(evt) {
     if (!this.active) {
       return;
     }
-
-      // Must move at least these many CSS pixels for it to count as a swipe
-      var SWIPE_MIN_DISTANCE_THRESHOLD = 50;
-      // The swipe angle is allowed to deviate from the x or y axis by this much
-      // before it is not considered a swipe in that direction any more.
-      var SWIPE_ANGLE_THRESHOLD = Math.PI / 6;
-
     if (evt.touches.length > 1) {
-        // Multiple touch points detected, cancel the swipe.
+      // Multiple touch points detected; cancel the swipe.
       this.touchSwipeState = null;
       return;
     }
+
     switch (evt.type) {
       case 'touchstart':
         this.touchSwipeState = {
           startX: evt.touches[0].pageX,
           startY: evt.touches[0].pageY,
           endX: evt.touches[0].pageX,
-            endY: evt.touches[0].pageY
+          endY: evt.touches[0].pageY,
         };
         break;
       case 'touchmove':
@@ -378,9 +365,8 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
         }
         this.touchSwipeState.endX = evt.touches[0].pageX;
         this.touchSwipeState.endY = evt.touches[0].pageY;
-          // Do a preventDefault to avoid the swipe from triggering browser
-          // gestures (Chrome in particular has some sort of swipe gesture in
-          // fullscreen mode).
+        // Avoid the swipe from triggering browser gestures (Chrome in
+        // particular has some sort of swipe gesture in fullscreen mode).
         evt.preventDefault();
         break;
       case 'touchend':
@@ -394,11 +380,11 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
         if (Math.abs(dx) > SWIPE_MIN_DISTANCE_THRESHOLD &&
             (absAngle <= SWIPE_ANGLE_THRESHOLD ||
              absAngle >= (Math.PI - SWIPE_ANGLE_THRESHOLD))) {
-            // horizontal swipe
+          // Horizontal swipe.
           delta = dx;
         } else if (Math.abs(dy) > SWIPE_MIN_DISTANCE_THRESHOLD &&
             Math.abs(absAngle - (Math.PI / 2)) <= SWIPE_ANGLE_THRESHOLD) {
-            // vertical swipe
+          // Vertical swipe.
           delta = dy;
         }
         if (delta > 0) {
@@ -408,12 +394,12 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
         }
         break;
     }
-    },
+  }
 
   /**
    * @private
    */
-    _addWindowListeners: function PDFPresentationMode_addWindowListeners() {
+  _addWindowListeners() {
     this.showControlsBind = this._showControls.bind(this);
     this.mouseDownBind = this._mouseDown.bind(this);
     this.mouseWheelBind = this._mouseWheel.bind(this);
@@ -429,13 +415,12 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
     window.addEventListener('touchstart', this.touchSwipeBind);
     window.addEventListener('touchmove', this.touchSwipeBind);
     window.addEventListener('touchend', this.touchSwipeBind);
-    },
+  }
 
   /**
    * @private
    */
-    _removeWindowListeners:
-        function PDFPresentationMode_removeWindowListeners() {
+  _removeWindowListeners() {
     window.removeEventListener('mousemove', this.showControlsBind);
     window.removeEventListener('mousedown', this.mouseDownBind);
     window.removeEventListener('wheel', this.mouseWheelBind);
@@ -451,24 +436,23 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
     delete this.resetMouseScrollStateBind;
     delete this.contextMenuBind;
     delete this.touchSwipeBind;
-    },
+  }
 
   /**
    * @private
    */
-    _fullscreenChange: function PDFPresentationMode_fullscreenChange() {
+  _fullscreenChange() {
     if (this.isFullscreen) {
       this._enter();
     } else {
       this._exit();
     }
-    },
+  }
 
   /**
    * @private
    */
-    _addFullscreenChangeListeners:
-        function PDFPresentationMode_addFullscreenChangeListeners() {
+  _addFullscreenChangeListeners() {
     this.fullscreenChangeBind = this._fullscreenChange.bind(this);
 
     window.addEventListener('fullscreenchange', this.fullscreenChangeBind);
@@ -480,13 +464,12 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
       window.addEventListener('MSFullscreenChange',
                               this.fullscreenChangeBind);
     }
-    },
+  }
 
   /**
    * @private
    */
-    _removeFullscreenChangeListeners:
-        function PDFPresentationMode_removeFullscreenChangeListeners() {
+  _removeFullscreenChangeListeners() {
     window.removeEventListener('fullscreenchange', this.fullscreenChangeBind);
     window.removeEventListener('mozfullscreenchange',
                                this.fullscreenChangeBind);
@@ -500,10 +483,7 @@ var PDFPresentationMode = (function PDFPresentationModeClosure() {
 
     delete this.fullscreenChangeBind;
   }
-  };
-
-  return PDFPresentationMode;
-})();
+}
 
 export {
   PDFPresentationMode,