hippofish/packages/frontend/src/scripts/focus-trap.ts

134 lines
3.7 KiB
TypeScript

/*
* SPDX-FileCopyrightText: syuilo and misskey-project
* SPDX-License-Identifier: AGPL-3.0-only
*/
import { getHTMLElementOrNull } from '@/scripts/get-dom-node-or-null.js';
const focusTrapElements = new Set<HTMLElement>();
const ignoreElements = [
'script',
'style',
];
function containsFocusTrappedElements(el: HTMLElement): boolean {
return Array.from(focusTrapElements).some((focusTrapElement) => {
return el.contains(focusTrapElement);
});
}
function getZIndex(el: HTMLElement): number {
const zIndex = parseInt(window.getComputedStyle(el).zIndex || '0', 10);
if (isNaN(zIndex)) {
return 0;
}
return zIndex;
}
function getHighestZIndexElement(): { el: HTMLElement; zIndex: number; } | null {
let highestZIndexElement: HTMLElement | null = null;
let highestZIndex = -Infinity;
focusTrapElements.forEach((el) => {
const zIndex = getZIndex(el);
if (zIndex > highestZIndex) {
highestZIndex = zIndex;
highestZIndexElement = el;
}
});
return highestZIndexElement == null ? null : {
el: highestZIndexElement,
zIndex: highestZIndex,
};
}
function releaseFocusTrap(el: HTMLElement): void {
focusTrapElements.delete(el);
if (el.inert === true) {
el.inert = false;
}
const highestZIndexElement = getHighestZIndexElement();
if (el.parentElement != null && el !== document.body) {
el.parentElement.childNodes.forEach((siblingNode) => {
const siblingEl = getHTMLElementOrNull(siblingNode);
if (!siblingEl) return;
if (
siblingEl !== el &&
(
highestZIndexElement == null ||
siblingEl === highestZIndexElement.el ||
siblingEl.contains(highestZIndexElement.el)
)
) {
siblingEl.inert = false;
} else if (
highestZIndexElement != null &&
siblingEl !== highestZIndexElement.el &&
!siblingEl.contains(highestZIndexElement.el) &&
!ignoreElements.includes(siblingEl.tagName.toLowerCase())
) {
siblingEl.inert = true;
} else {
siblingEl.inert = false;
}
});
releaseFocusTrap(el.parentElement);
}
}
export function focusTrap(el: HTMLElement, hasInteractionWithOtherFocusTrappedEls: boolean, parent: true): void;
export function focusTrap(el: HTMLElement, hasInteractionWithOtherFocusTrappedEls?: boolean, parent?: false): { release: () => void; };
export function focusTrap(el: HTMLElement, hasInteractionWithOtherFocusTrappedEls = false, parent = false): { release: () => void; } | void {
const highestZIndexElement = getHighestZIndexElement();
const highestZIndex = highestZIndexElement == null ? -Infinity : highestZIndexElement.zIndex;
const zIndex = getZIndex(el);
// If the element has a lower z-index than the highest z-index element, focus trap the highest z-index element instead
// Focus trapping for this element will be done in the release function
if (!parent && zIndex < highestZIndex) {
focusTrapElements.add(el);
if (highestZIndexElement) {
focusTrap(highestZIndexElement.el, hasInteractionWithOtherFocusTrappedEls);
}
return {
release: () => {
releaseFocusTrap(el);
},
};
}
if (el.inert === true) {
el.inert = false;
}
if (el.parentElement != null && el !== document.body) {
el.parentElement.childNodes.forEach((siblingNode) => {
const siblingEl = getHTMLElementOrNull(siblingNode);
if (!siblingEl) return;
if (
siblingEl !== el &&
(
hasInteractionWithOtherFocusTrappedEls === false ||
(!focusTrapElements.has(siblingEl) && !containsFocusTrappedElements(siblingEl))
) &&
!ignoreElements.includes(siblingEl.tagName.toLowerCase())
) {
siblingEl.inert = true;
}
});
focusTrap(el.parentElement, hasInteractionWithOtherFocusTrappedEls, true);
}
if (!parent) {
focusTrapElements.add(el);
return {
release: () => {
releaseFocusTrap(el);
},
};
}
}