@octopusdeploy/design-system-components/dist/src/hooks/useFocusTrap.js

The design systems component library.

"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
exports.useFocusTrap = useFocusTrap;
exports.useFocusFirstFocusableElement = useFocusFirstFocusableElement;
const react_1 = __importStar(require("react"));
const isHTMLElement_1 = require("../utils/isHTMLElement");
/**
 * Traps focus within a DOM node. Shifting focus with `Tab` and `Shift-Tab` will loop through all focusable elements of the node.
 * Nesting is handled naturally by the browser's event model — keydown events only bubble through DOM ancestors,
 * so a trap only fires when focus is actually inside its container.
 */
function useFocusTrap(focusContainer, enabled = true) {
    (0, react_1.useEffect)(() => {
        if (!focusContainer || !enabled)
            return;
        const onKeyDown = (event) => {
            if (event.key !== "Tab")
                return;
            const tabbableElements = Array.from(focusContainer.querySelectorAll(focusableSelector)).filter(isTabbableElement);
            if (tabbableElements.length === 0)
                return;
            const firstFocusableElement = tabbableElements[0];
            const lastFocusableElement = tabbableElements[tabbableElements.length - 1];
            // If focus is on a non-tabbable element, e.g. initial focus on a dialog container with tabIndex -1, move to first or last element depending on direction.
            if (document.activeElement && !isTabbableElement(document.activeElement)) {
                if (event.shiftKey) {
                    lastFocusableElement?.focus();
                }
                else {
                    firstFocusableElement?.focus();
                }
                event.preventDefault();
                return;
            }
            // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
            const currentIndex = tabbableElements.indexOf(document.activeElement);
            // Always handle Tab ourselves so focus order follows DOM order. This prevents browsers from
            // skipping elements outside scrollable containers (e.g. dialog footer buttons).
            event.preventDefault();
            if (event.shiftKey) {
                const prevIndex = currentIndex === 0 ? tabbableElements.length - 1 : currentIndex - 1;
                tabbableElements[prevIndex].focus();
            }
            else {
                const nextIndex = currentIndex === tabbableElements.length - 1 ? 0 : currentIndex + 1;
                tabbableElements[nextIndex].focus();
            }
        };
        focusContainer.addEventListener("keydown", onKeyDown);
        return () => {
            focusContainer.removeEventListener("keydown", onKeyDown);
        };
    }, [focusContainer, enabled]);
}
function useFocusFirstFocusableElement() {
    return react_1.default.useCallback((container) => {
        const [firstFocusableElement] = Array.from(container.querySelectorAll(focusableSelector)).filter(isTabbableElement);
        if (firstFocusableElement) {
            firstFocusableElement.focus();
        }
        else if (container.tabIndex >= 0) {
            container.focus();
        }
    }, []);
}
// From https://github.com/testing-library/user-event/blob/main/src/utils/focus/selector.ts
const focusableSelector = ["input:not([type=hidden]):not([disabled])", "button:not([disabled])", "select:not([disabled])", "textarea:not([disabled])", '[contenteditable=""]', '[contenteditable="true"]', "a[href]", "[tabindex]:not([disabled])"].join(", ");
function isTabbableElement(element) {
    if (!(0, isHTMLElement_1.isHTMLElement)(element))
        return false;
    if (element.tabIndex < 0)
        return false;
    // Exclude elements inside an inert subtree — inert removes them from tab order but tabIndex doesn't reflect it.
    if (element.closest("[inert]"))
        return false;
    if (!isVisible(element))
        return false;
    return true;
}
function isVisible(element) {
    if (element.hidden)
        return false;
    // Fast path: non-null offsetParent means the element is definitely rendered in a real browser.
    // In jsdom offsetParent is always null, so this never short-circuits there.
    if (element.offsetParent !== null)
        return true;
    // offsetParent is null in three cases: display:none (self or ancestor), position:fixed, or jsdom.
    // Check the element's own computed styles first to catch explicit display:none / visibility:hidden.
    const style = getComputedStyle(element);
    if (style.display === "none" || style.visibility === "hidden")
        return false;
    // Use getClientRects() to catch ancestor display:none (e.g. a side panel hidden via a media
    // query) since getComputedStyle only reflects the element's own styles. position:fixed elements
    // still produce rects so they pass correctly. In jsdom getClientRects() always returns [] so
    // guard with a body probe — body always has rects in a real browser but not in jsdom.
    // TODO: Remove the body probe and inline condition once tests run under Vitest browser mode,
    // leaving just: if (element.getClientRects().length === 0) return false;
    if (element.getClientRects().length === 0 && document.body.getClientRects().length > 0)
        return false;
    return true;
}