136 lines
6.0 KiB
JavaScript
136 lines
6.0 KiB
JavaScript
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/**
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* @license
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* Copyright 2020 Google Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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var FOCUS_SENTINEL_CLASS = 'mdc-dom-focus-sentinel';
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/**
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* Utility to trap focus in a given root element, e.g. for modal components such
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* as dialogs. The root should have at least one focusable child element,
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* for setting initial focus when trapping focus.
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* Also tracks the previously focused element, and restores focus to that
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* element when releasing focus.
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*/
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var FocusTrap = /** @class */ (function () {
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function FocusTrap(root, options) {
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if (options === void 0) { options = {}; }
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this.root = root;
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this.options = options;
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// Previously focused element before trapping focus.
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this.elFocusedBeforeTrapFocus = null;
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}
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/**
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* Traps focus in `root`. Also focuses on either `initialFocusEl` if set;
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* otherwises sets initial focus to the first focusable child element.
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*/
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FocusTrap.prototype.trapFocus = function () {
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var focusableEls = this.getFocusableElements(this.root);
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if (focusableEls.length === 0) {
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throw new Error('FocusTrap: Element must have at least one focusable child.');
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}
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this.elFocusedBeforeTrapFocus =
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document.activeElement instanceof HTMLElement ? document.activeElement :
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null;
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this.wrapTabFocus(this.root);
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if (!this.options.skipInitialFocus) {
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this.focusInitialElement(focusableEls, this.options.initialFocusEl);
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}
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};
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/**
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* Releases focus from `root`. Also restores focus to the previously focused
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* element.
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*/
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FocusTrap.prototype.releaseFocus = function () {
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[].slice.call(this.root.querySelectorAll("." + FOCUS_SENTINEL_CLASS))
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.forEach(function (sentinelEl) {
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sentinelEl.parentElement.removeChild(sentinelEl);
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});
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if (!this.options.skipRestoreFocus && this.elFocusedBeforeTrapFocus) {
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this.elFocusedBeforeTrapFocus.focus();
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}
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};
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/**
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* Wraps tab focus within `el` by adding two hidden sentinel divs which are
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* used to mark the beginning and the end of the tabbable region. When
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* focused, these sentinel elements redirect focus to the first/last
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* children elements of the tabbable region, ensuring that focus is trapped
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* within that region.
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*/
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FocusTrap.prototype.wrapTabFocus = function (el) {
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var _this = this;
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var sentinelStart = this.createSentinel();
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var sentinelEnd = this.createSentinel();
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sentinelStart.addEventListener('focus', function () {
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var focusableEls = _this.getFocusableElements(el);
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if (focusableEls.length > 0) {
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focusableEls[focusableEls.length - 1].focus();
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}
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});
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sentinelEnd.addEventListener('focus', function () {
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var focusableEls = _this.getFocusableElements(el);
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if (focusableEls.length > 0) {
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focusableEls[0].focus();
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}
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});
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el.insertBefore(sentinelStart, el.children[0]);
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el.appendChild(sentinelEnd);
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};
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/**
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* Focuses on `initialFocusEl` if defined and a child of the root element.
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* Otherwise, focuses on the first focusable child element of the root.
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*/
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FocusTrap.prototype.focusInitialElement = function (focusableEls, initialFocusEl) {
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var focusIndex = 0;
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if (initialFocusEl) {
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focusIndex = Math.max(focusableEls.indexOf(initialFocusEl), 0);
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}
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focusableEls[focusIndex].focus();
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};
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FocusTrap.prototype.getFocusableElements = function (root) {
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var focusableEls = [].slice.call(root.querySelectorAll('[autofocus], [tabindex], a, input, textarea, select, button'));
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return focusableEls.filter(function (el) {
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var isDisabledOrHidden = el.getAttribute('aria-disabled') === 'true' ||
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el.getAttribute('disabled') != null ||
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el.getAttribute('hidden') != null ||
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el.getAttribute('aria-hidden') === 'true';
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var isTabbableAndVisible = el.tabIndex >= 0 &&
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el.getBoundingClientRect().width > 0 &&
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!el.classList.contains(FOCUS_SENTINEL_CLASS) && !isDisabledOrHidden;
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var isProgrammaticallyHidden = false;
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if (isTabbableAndVisible) {
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var style = getComputedStyle(el);
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isProgrammaticallyHidden =
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style.display === 'none' || style.visibility === 'hidden';
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}
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return isTabbableAndVisible && !isProgrammaticallyHidden;
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});
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};
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FocusTrap.prototype.createSentinel = function () {
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var sentinel = document.createElement('div');
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sentinel.setAttribute('tabindex', '0');
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// Don't announce in screen readers.
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sentinel.setAttribute('aria-hidden', 'true');
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sentinel.classList.add(FOCUS_SENTINEL_CLASS);
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return sentinel;
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};
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return FocusTrap;
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}());
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export { FocusTrap };
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//# sourceMappingURL=focus-trap.js.map
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