Remove up/down to flip keyboard shortcut

This gets confusing when combined with slider focus, where the shortcut does potentially the opposite of what it appears to do.

Author: cdrini

src/BookReader.js

@@ -876,18 +876,14 @@ BookReader.prototype.setupKeyListeners = function () {
       e.preventDefault();
       this.last();
       break;
-    case "ArrowDown":
     case "PageDown":
-    case "Down": // hack for IE and old Gecko
       // In 1up and thumb mode page scrolling handled by browser
       if (this.constMode2up === this.mode) {
         e.preventDefault();
         this.next();
       }
       break;
-    case "ArrowUp":
     case "PageUp":
-    case "Up": // hack for IE and old Gecko
       // In 1up and thumb mode page scrolling handled by browser
       if (this.constMode2up === this.mode) {
         e.preventDefault();

src/BookReader/Navbar/Navbar.js

@@ -328,6 +328,23 @@ export class Navbar {
       'aria-valuemax': br.book.getNumLeafs(),
     });
 
+    // Ignore up/down arrow keys and page up/down keys, since they're confusingly different
+    // between slider movement and page movement. Down decreases slider value, which would move
+    // the scroll _up_ in 1up.
+    $sliders.find('.ui-slider-handle').off('keydown').on('keydown', function (event) {
+      switch (event.keyCode || event.which) {
+      case $.ui.keyCode.UP:
+      case $.ui.keyCode.DOWN:
+      case $.ui.keyCode.PAGE_UP:
+      case $.ui.keyCode.PAGE_DOWN:
+        return;
+      default:
+        // Forward along to the default handler for other keys
+        $.ui.slider.prototype._handleEvents.keydown.call($(this).parent().data('ui-slider'), event);
+        return;
+      }
+    });
+
     $sliders.on('slide', (event, ui) => this.updateNavPageNum(ui.value));
 
     $sliders.on('slidechange', (event, ui) => {

tests/jest/BookReader.keyboard.test.js

@@ -73,16 +73,6 @@ describe('Keyboard shortcuts', () => {
     expect(keyEvent.preventDefault).toHaveBeenCalledTimes(1);
   });
 
-  test('ArrowDown key', () => {
-    br.mode = br.constMode2up;
-    br.next = jest.fn();
-    const keyEvent = new KeyboardEvent('keydown', {'key': 'ArrowDown'});
-    keyEvent.preventDefault = jest.fn();
-    document.dispatchEvent(keyEvent);
-    expect(br.next).toHaveBeenCalledTimes(1);
-    expect(keyEvent.preventDefault).toHaveBeenCalledTimes(1);
-  });
-
   test('PageDown key', () => {
     br.mode = br.constMode2up;
     br.next = jest.fn();
@@ -93,16 +83,6 @@ describe('Keyboard shortcuts', () => {
     expect(keyEvent.preventDefault).toHaveBeenCalledTimes(1);
   });
 
-  test('ArrowUp key', () => {
-    br.mode = br.constMode2up;
-    br.prev = jest.fn();
-    const keyEvent = new KeyboardEvent('keydown', {'key': 'ArrowUp'});
-    keyEvent.preventDefault = jest.fn();
-    document.dispatchEvent(keyEvent);
-    expect(br.prev).toHaveBeenCalledTimes(1);
-    expect(keyEvent.preventDefault).toHaveBeenCalledTimes(1);
-  });
-
   test('PageUp key', () => {
     br.mode = br.constMode2up;
     br.prev = jest.fn();