From 2d13ad3d397423e527caa6f3eba9df242505dfff Mon Sep 17 00:00:00 2001
From: Sam Potts <sam@potts.es>
Date: Sun, 9 Feb 2020 21:42:12 +0000
Subject: [PATCH] Focus trap improvements

---
 src/js/fullscreen.js     | 173 ++++++++++++++++++++++-----------------
 src/js/utils/elements.js |  35 --------
 2 files changed, 99 insertions(+), 109 deletions(-)

diff --git a/src/js/fullscreen.js b/src/js/fullscreen.js
index 7ae3ff17..c74b3406 100644
--- a/src/js/fullscreen.js
+++ b/src/js/fullscreen.js
@@ -5,79 +5,10 @@
 // ==========================================================================
 
 import browser from './utils/browser';
-import { hasClass, toggleClass, trapFocus } from './utils/elements';
+import { getElements, hasClass, toggleClass } from './utils/elements';
 import { on, triggerEvent } from './utils/events';
 import is from './utils/is';
 
-function onChange() {
-    if (!this.enabled) {
-        return;
-    }
-
-    // Update toggle button
-    const button = this.player.elements.buttons.fullscreen;
-    if (is.element(button)) {
-        button.pressed = this.active;
-    }
-
-    // Trigger an event
-    triggerEvent.call(this.player, this.target, this.active ? 'enterfullscreen' : 'exitfullscreen', true);
-
-    // Trap focus in container
-    if (!browser.isIos) {
-        trapFocus.call(this.player, this.target, this.active);
-    }
-}
-
-function toggleFallback(toggle = false) {
-    // Store or restore scroll position
-    if (toggle) {
-        this.scrollPosition = {
-            x: window.scrollX || 0,
-            y: window.scrollY || 0,
-        };
-    } else {
-        window.scrollTo(this.scrollPosition.x, this.scrollPosition.y);
-    }
-
-    // Toggle scroll
-    document.body.style.overflow = toggle ? 'hidden' : '';
-
-    // Toggle class hook
-    toggleClass(this.target, this.player.config.classNames.fullscreen.fallback, toggle);
-
-    // Force full viewport on iPhone X+
-    if (browser.isIos) {
-        let viewport = document.head.querySelector('meta[name="viewport"]');
-        const property = 'viewport-fit=cover';
-
-        // Inject the viewport meta if required
-        if (!viewport) {
-            viewport = document.createElement('meta');
-            viewport.setAttribute('name', 'viewport');
-        }
-
-        // Check if the property already exists
-        const hasProperty = is.string(viewport.content) && viewport.content.includes(property);
-
-        if (toggle) {
-            this.cleanupViewport = !hasProperty;
-
-            if (!hasProperty) {
-                viewport.content += `,${property}`;
-            }
-        } else if (this.cleanupViewport) {
-            viewport.content = viewport.content
-                .split(',')
-                .filter(part => part.trim() !== property)
-                .join(',');
-        }
-    }
-
-    // Toggle button and fire events
-    onChange.call(this);
-}
-
 class Fullscreen {
     constructor(player) {
         // Keep reference to parent
@@ -101,7 +32,7 @@ class Fullscreen {
             this.prefix === 'ms' ? 'MSFullscreenChange' : `${this.prefix}fullscreenchange`,
             () => {
                 // TODO: Filter for target??
-                onChange.call(this);
+                this.onChange();
             },
         );
 
@@ -115,6 +46,9 @@ class Fullscreen {
             this.toggle();
         });
 
+        // Tap focus when in fullscreen
+        on.call(this, this.player.elements.container, 'keydown', event => this.trapFocus(event));
+
         // Update the UI
         this.update();
     }
@@ -194,6 +128,97 @@ class Fullscreen {
             : this.player.elements.container;
     }
 
+    onChange() {
+        if (!this.enabled) {
+            return;
+        }
+
+        // Update toggle button
+        const button = this.player.elements.buttons.fullscreen;
+        if (is.element(button)) {
+            button.pressed = this.active;
+        }
+
+        // Trigger an event
+        triggerEvent.call(this.player, this.target, this.active ? 'enterfullscreen' : 'exitfullscreen', true);
+    }
+
+    toggleFallback(toggle = false) {
+        // Store or restore scroll position
+        if (toggle) {
+            this.scrollPosition = {
+                x: window.scrollX || 0,
+                y: window.scrollY || 0,
+            };
+        } else {
+            window.scrollTo(this.scrollPosition.x, this.scrollPosition.y);
+        }
+
+        // Toggle scroll
+        document.body.style.overflow = toggle ? 'hidden' : '';
+
+        // Toggle class hook
+        toggleClass(this.target, this.player.config.classNames.fullscreen.fallback, toggle);
+
+        // Force full viewport on iPhone X+
+        if (browser.isIos) {
+            let viewport = document.head.querySelector('meta[name="viewport"]');
+            const property = 'viewport-fit=cover';
+
+            // Inject the viewport meta if required
+            if (!viewport) {
+                viewport = document.createElement('meta');
+                viewport.setAttribute('name', 'viewport');
+            }
+
+            // Check if the property already exists
+            const hasProperty = is.string(viewport.content) && viewport.content.includes(property);
+
+            if (toggle) {
+                this.cleanupViewport = !hasProperty;
+
+                if (!hasProperty) {
+                    viewport.content += `,${property}`;
+                }
+            } else if (this.cleanupViewport) {
+                viewport.content = viewport.content
+                    .split(',')
+                    .filter(part => part.trim() !== property)
+                    .join(',');
+            }
+        }
+
+        // Toggle button and fire events
+        this.onChange();
+    }
+
+    // Trap focus inside container
+    trapFocus(event) {
+        // Bail if iOS, not active, not the tab key
+        if (browser.isIos || !this.active || event.key !== 'Tab' || event.keyCode !== 9) {
+            return;
+        }
+
+        // Get the current focused element
+        const focused = document.activeElement;
+        const focusable = getElements.call(
+            this.player,
+            'a[href], button:not(:disabled), input:not(:disabled), [tabindex]',
+        );
+        const [first] = focusable;
+        const last = focusable[focusable.length - 1];
+
+        if (focused === last && !event.shiftKey) {
+            // Move focus to first element that can be tabbed if Shift isn't used
+            first.focus();
+            event.preventDefault();
+        } else if (focused === first && event.shiftKey) {
+            // Move focus to last element that can be tabbed if Shift is used
+            last.focus();
+            event.preventDefault();
+        }
+    }
+
     // Update UI
     update() {
         if (this.enabled) {
@@ -226,9 +251,9 @@ class Fullscreen {
         if (browser.isIos && this.player.config.fullscreen.iosNative) {
             this.target.webkitEnterFullscreen();
         } else if (!Fullscreen.native || this.forceFallback) {
-            toggleFallback.call(this, true);
+            this.toggleFallback(true);
         } else if (!this.prefix) {
-            this.target.requestFullscreen({ navigationUI: "hide" });
+            this.target.requestFullscreen({ navigationUI: 'hide' });
         } else if (!is.empty(this.prefix)) {
             this.target[`${this.prefix}Request${this.property}`]();
         }
@@ -245,7 +270,7 @@ class Fullscreen {
             this.target.webkitExitFullscreen();
             this.player.play();
         } else if (!Fullscreen.native || this.forceFallback) {
-            toggleFallback.call(this, false);
+            this.toggleFallback(false);
         } else if (!this.prefix) {
             (document.cancelFullScreen || document.exitFullscreen).call(document);
         } else if (!is.empty(this.prefix)) {
diff --git a/src/js/utils/elements.js b/src/js/utils/elements.js
index 921d533a..b88aad0c 100644
--- a/src/js/utils/elements.js
+++ b/src/js/utils/elements.js
@@ -2,7 +2,6 @@
 // Element utils
 // ==========================================================================
 
-import { toggleListener } from './events';
 import is from './is';
 import { extend } from './objects';
 
@@ -248,40 +247,6 @@ export function getElement(selector) {
     return this.elements.container.querySelector(selector);
 }
 
-// Trap focus inside container
-export function trapFocus(element = null, toggle = false) {
-    if (!is.element(element)) {
-        return;
-    }
-
-    const focusable = getElements.call(this, 'button:not(:disabled), input:not(:disabled), [tabindex]');
-    const first = focusable[0];
-    const last = focusable[focusable.length - 1];
-    const player = this;
-
-    const trap = event => {
-        // Bail if not tab key or not fullscreen
-        if (event.key !== 'Tab' || event.keyCode !== 9 || !player.fullscreen.active) {
-            return;
-        }
-
-        // Get the current focused element
-        const focused = document.activeElement;
-
-        if (focused === last && !event.shiftKey) {
-            // Move focus to first element that can be tabbed if Shift isn't used
-            first.focus();
-            event.preventDefault();
-        } else if (focused === first && event.shiftKey) {
-            // Move focus to last element that can be tabbed if Shift is used
-            last.focus();
-            event.preventDefault();
-        }
-    };
-
-    toggleListener.call(this, this.elements.container, 'keydown', trap, toggle, false);
-}
-
 // Set focus and tab focus class
 export function setFocus(element = null, tabFocus = false) {
     if (!is.element(element)) {