Merge branch 'main' into prettier

bookwyrm/static/js/bookwyrm.js

@@ -34,6 +34,10 @@ let BookWyrm = new (class {
             .querySelectorAll('input[type="file"]')
             .forEach((node) => node.addEventListener("change", this.disableIfTooLarge.bind(this)));
 
+        document
+            .querySelectorAll("button[data-modal-open]")
+            .forEach((node) => node.addEventListener("click", this.handleModalButton.bind(this)));
+
         document
             .querySelectorAll("[data-duplicate]")
             .forEach((node) => node.addEventListener("click", this.duplicateInput.bind(this)));
@@ -400,6 +404,93 @@ let BookWyrm = new (class {
         }
     }
 
+    /**
+     * Handle the modal component.
+     *
+     * @param  {Event} event - Event fired by an element
+     *                         with the `data-modal-open` attribute
+     *                         pointing to a modal by its id.
+     * @return {undefined}
+     *
+     * See https://github.com/bookwyrm-social/bookwyrm/pull/1633
+     *  for information about using the modal.
+     */
+    handleModalButton(event) {
+        const modalButton = event.currentTarget;
+        const targetModalId = modalButton.dataset.modalOpen;
+        const htmlElement = document.querySelector("html");
+        const modal = document.getElementById(targetModalId);
+
+        if (!modal) {
+            return;
+        }
+
+        // Helper functions
+        function handleModalOpen(modalElement) {
+            htmlElement.classList.add("is-clipped");
+            modalElement.classList.add("is-active");
+            modalElement.getElementsByClassName("modal-card")[0].focus();
+
+            const closeButtons = modalElement.querySelectorAll("[data-modal-close]");
+
+            closeButtons.forEach((button) => {
+                button.addEventListener("click", function () {
+                    handleModalClose(modalElement);
+                });
+            });
+
+            document.addEventListener("keydown", function (event) {
+                if (event.key === "Escape") {
+                    handleModalClose(modalElement);
+                }
+            });
+
+            modalElement.addEventListener("keydown", handleFocusTrap);
+        }
+
+        function handleModalClose(modalElement) {
+            modalElement.removeEventListener("keydown", handleFocusTrap);
+            htmlElement.classList.remove("is-clipped");
+            modalElement.classList.remove("is-active");
+            modalButton.focus();
+        }
+
+        function handleFocusTrap(event) {
+            if (event.key !== "Tab") {
+                return;
+            }
+
+            const focusableEls = event.currentTarget.querySelectorAll(
+                [
+                    "a[href]:not([disabled])",
+                    "button:not([disabled])",
+                    "textarea:not([disabled])",
+                    'input:not([type="hidden"]):not([disabled])',
+                    "select:not([disabled])",
+                    "details:not([disabled])",
+                    '[tabindex]:not([tabindex="-1"]):not([disabled])',
+                ].join(",")
+            );
+            const firstFocusableEl = focusableEls[0];
+            const lastFocusableEl = focusableEls[focusableEls.length - 1];
+
+            if (event.shiftKey) {
+                /* Shift + tab */ if (document.activeElement === firstFocusableEl) {
+                    lastFocusableEl.focus();
+                    event.preventDefault();
+                }
+            } /* Tab */ else {
+                if (document.activeElement === lastFocusableEl) {
+                    firstFocusableEl.focus();
+                    event.preventDefault();
+                }
+            }
+        }
+
+        // Open modal
+        handleModalOpen(modal);
+    }
+
     /**
      * Display pop up window.
      *