Refactor video modal accessibility wiring

js/ui/components/VideoModal.js

@@ -1,3 +1,5 @@
+import { createModalAccessibility } from "./modalAccessibility.js";
+
 export class VideoModal {
   constructor({
     removeTrackingScripts,
@@ -25,6 +27,8 @@ export class VideoModal {
     this.loaded = false;
 
     this.playerModal = null;
+    this.modalPanel = null;
+    this.modalBackdrop = null;
     this.scrollRegion = null;
     this.modalVideo = null;
     this.modalStatus = null;
@@ -46,6 +50,9 @@ export class VideoModal {
     this.modalMoreBtn = null;
     this.modalMoreMenu = null;
 
+    this.modalAccessibility = null;
+    this.modalNavScrollHandler = null;
+
     this.modalZapDialog = null;
     this.modalZapForm = null;
     this.modalZapAmountInput = null;
@@ -190,9 +197,23 @@ export class VideoModal {
   }
 
   hydrate(playerModal) {
+    if (this.modalAccessibility?.destroy) {
+      this.modalAccessibility.destroy();
+    }
+    this.modalAccessibility = null;
+
+    const previousScrollRegion = this.scrollRegion;
+    if (previousScrollRegion && this.modalNavScrollHandler) {
+      previousScrollRegion.removeEventListener(
+        "scroll",
+        this.modalNavScrollHandler
+      );
+    }
+
     this.playerModal = playerModal;
-    this.scrollRegion =
-      playerModal.querySelector(".player-modal__content") || playerModal;
+    this.modalPanel = playerModal.querySelector(".bv-modal__panel") || null;
+    this.modalBackdrop = playerModal.querySelector("[data-dismiss]") || null;
+    this.scrollRegion = this.modalPanel || playerModal;
 
     this.modalVideo = playerModal.querySelector("#modalVideo") || null;
     this.modalStatus = playerModal.querySelector("#modalStatus") || null;
@@ -253,7 +274,7 @@ export class VideoModal {
     const modalNav = playerModal.querySelector("#modalNav");
     if (modalNav && this.scrollRegion) {
       let lastScrollY = 0;
-      this.scrollRegion.addEventListener("scroll", () => {
+      this.modalNavScrollHandler = () => {
         const currentScrollY = this.scrollRegion.scrollTop;
         const shouldShowNav =
           currentScrollY <= lastScrollY || currentScrollY < 50;
@@ -261,9 +282,22 @@ export class VideoModal {
           ? "translateY(0)"
           : "translateY(-100%)";
         lastScrollY = currentScrollY;
-      });
+      };
+      this.scrollRegion.addEventListener("scroll", this.modalNavScrollHandler);
+    } else {
+      this.modalNavScrollHandler = null;
     }
 
+    this.modalAccessibility = createModalAccessibility({
+      root: this.playerModal,
+      panel: this.modalPanel,
+      backdrop: this.modalBackdrop,
+      document: this.document,
+      onRequestClose: () => {
+        this.dispatch("modal:close", { video: this.activeVideo });
+      },
+    });
+
     this.bindVideoEvents();
     this.bindActionButtons();
     this.setZapVisibility(false);
@@ -427,34 +461,6 @@ export class VideoModal {
     this.dispatch("creator:navigate", { video: this.activeVideo });
   }
 
-  toggleBackgroundInert(enable) {
-    const ids = ["sidebar", "sidebarOverlay"];
-    for (const id of ids) {
-      const element = this.document.getElementById(id);
-      if (!element) {
-        continue;
-      }
-
-      if (enable) {
-        if (!element.hasAttribute("inert")) {
-          element.setAttribute("inert", "");
-        }
-        element.dataset.modalInert = "true";
-        element.setAttribute("aria-hidden", "true");
-        element.classList.add("is-modal-hidden");
-      } else {
-        if (element.dataset.modalInert === "true") {
-          element.removeAttribute("inert");
-          delete element.dataset.modalInert;
-        }
-        if (element.getAttribute("aria-hidden") === "true") {
-          element.removeAttribute("aria-hidden");
-        }
-        element.classList.remove("is-modal-hidden");
-      }
-    }
-  }
-
   open(video) {
     this.activeVideo = video || null;
     if (!this.playerModal) {
@@ -465,7 +471,7 @@ export class VideoModal {
     this.playerModal.classList.remove("hidden");
     this.document.body.classList.add("modal-open");
     this.document.documentElement.classList.add("modal-open");
-    this.toggleBackgroundInert(true);
+    this.modalAccessibility?.activate();
     if (this.scrollRegion) {
       this.scrollRegion.scrollTop = 0;
     }
@@ -481,7 +487,7 @@ export class VideoModal {
     }
     this.document.body.classList.remove("modal-open");
     this.document.documentElement.classList.remove("modal-open");
-    this.toggleBackgroundInert(false);
+    this.modalAccessibility?.deactivate();
     this.setGlobalModalState("player", false);
     this.forceRemovePoster("close");
   }

js/ui/components/modalAccessibility.js

@@ -0,0 +1,192 @@
+const FOCUSABLE_SELECTORS = [
+  "a[href]",
+  "area[href]",
+  "button:not([disabled])",
+  'input:not([type="hidden"]):not([disabled])',
+  "select:not([disabled])",
+  "textarea:not([disabled])",
+  "iframe",
+  "object",
+  "embed",
+  '[contenteditable="true"]',
+  "[tabindex]",
+  "audio[controls]",
+  "video[controls]",
+].join(",");
+
+const scheduleMicrotask =
+  typeof queueMicrotask === "function"
+    ? queueMicrotask
+    : (callback) => Promise.resolve().then(callback);
+
+function isFocusable(element) {
+  if (!element) {
+    return false;
+  }
+  if (element.hasAttribute('disabled')) {
+    return false;
+  }
+  const tabindex = element.getAttribute('tabindex');
+  if (tabindex && Number(tabindex) < 0) {
+    return false;
+  }
+  if (element.getAttribute('aria-hidden') === 'true') {
+    return false;
+  }
+  const rects = element.getClientRects();
+  if (rects.length === 0) {
+    return false;
+  }
+  return true;
+}
+
+export function createModalAccessibility({ root, panel, backdrop, document: providedDocument, onRequestClose } = {}) {
+  const doc = providedDocument || root?.ownerDocument || (typeof document !== 'undefined' ? document : null);
+  if (!root || !panel || !doc) {
+    return {
+      activate() {},
+      deactivate() {},
+      destroy() {},
+      isActive() {
+        return false;
+      },
+    };
+  }
+
+  let active = false;
+  let previousFocus = null;
+
+  const resolveDismissTarget = (target) => {
+    if (!target) {
+      return null;
+    }
+    if (
+      backdrop &&
+      (target === backdrop || backdrop.contains?.(target)) &&
+      !backdrop.hasAttribute("data-dismiss")
+    ) {
+      return backdrop;
+    }
+    return target.closest?.("[data-dismiss]") || null;
+  };
+
+  const keydownListener = (event) => {
+    if (!active) {
+      return;
+    }
+    if (event.key === "Escape") {
+      if (root.contains(event.target)) {
+        event.preventDefault();
+      }
+      onRequestClose?.(event);
+      return;
+    }
+    if (event.key !== "Tab" || !root.contains(event.target)) {
+      return;
+    }
+
+    const focusable = Array.from(panel.querySelectorAll(FOCUSABLE_SELECTORS)).filter(isFocusable);
+    const activeElement = doc.activeElement;
+    const isPanelFocused = activeElement === panel;
+
+    if (focusable.length === 0) {
+      event.preventDefault();
+      if (panel !== activeElement) {
+        panel.focus({ preventScroll: true });
+      }
+      return;
+    }
+
+    const first = focusable[0];
+    const last = focusable[focusable.length - 1];
+
+    if (event.shiftKey) {
+      if (activeElement === first || !panel.contains(activeElement) || isPanelFocused) {
+        event.preventDefault();
+        last.focus({ preventScroll: true });
+      }
+      return;
+    }
+
+    if (activeElement === last || isPanelFocused) {
+      event.preventDefault();
+      first.focus({ preventScroll: true });
+    }
+  };
+
+  const clickListener = (event) => {
+    if (!active) {
+      return;
+    }
+    const dismissTarget = resolveDismissTarget(event.target);
+    if (!dismissTarget) {
+      return;
+    }
+    if (!root.contains(dismissTarget)) {
+      return;
+    }
+    event.preventDefault();
+    event.stopPropagation();
+    onRequestClose?.(event);
+  };
+
+  const activate = () => {
+    if (active) {
+      return;
+    }
+    active = true;
+    const activeElement = doc.activeElement;
+    previousFocus = activeElement instanceof Element ? activeElement : null;
+    doc.addEventListener("keydown", keydownListener, true);
+    root.addEventListener("click", clickListener);
+    if (backdrop && backdrop !== root) {
+      backdrop.addEventListener("click", clickListener);
+    }
+
+    scheduleMicrotask(() => {
+      if (!active) {
+        return;
+      }
+      const focusTarget = Array.from(panel.querySelectorAll(FOCUSABLE_SELECTORS)).find(isFocusable) || panel;
+      if (typeof focusTarget.focus === "function") {
+        focusTarget.focus({ preventScroll: true });
+      }
+    });
+  };
+
+  const deactivate = () => {
+    if (!active) {
+      return;
+    }
+    doc.removeEventListener("keydown", keydownListener, true);
+    root.removeEventListener("click", clickListener);
+    if (backdrop && backdrop !== root) {
+      backdrop.removeEventListener("click", clickListener);
+    }
+    active = false;
+
+    if (previousFocus && typeof previousFocus.focus === "function") {
+      if (
+        !root.contains(previousFocus) &&
+        typeof doc.contains === "function" &&
+        doc.contains(previousFocus)
+      ) {
+        previousFocus.focus({ preventScroll: true });
+      }
+    }
+    previousFocus = null;
+  };
+
+  const destroy = () => {
+    deactivate();
+  };
+
+  return {
+    activate,
+    deactivate,
+    destroy,
+    isActive() {
+      return active;
+    },
+  };
+}