@material/dom
Version:
DOM manipulation utilities for Material Components for the web
136 lines • 6.13 kB
JavaScript
/**
* @license
* Copyright 2020 Google Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
var FOCUS_SENTINEL_CLASS = 'mdc-dom-focus-sentinel';
/**
* Utility to trap focus in a given root element, e.g. for modal components such
* as dialogs. The root should have at least one focusable child element,
* for setting initial focus when trapping focus.
* Also tracks the previously focused element, and restores focus to that
* element when releasing focus.
*/
var FocusTrap = /** @class */ (function () {
function FocusTrap(root, options) {
if (options === void 0) { options = {}; }
this.root = root;
this.options = options;
// Previously focused element before trapping focus.
this.elFocusedBeforeTrapFocus = null;
}
/**
* Traps focus in `root`. Also focuses on either `initialFocusEl` if set;
* otherwises sets initial focus to the first focusable child element.
*/
FocusTrap.prototype.trapFocus = function () {
var focusableEls = this.getFocusableElements(this.root);
if (focusableEls.length === 0) {
throw new Error('FocusTrap: Element must have at least one focusable child.');
}
this.elFocusedBeforeTrapFocus =
document.activeElement instanceof HTMLElement ? document.activeElement :
null;
this.wrapTabFocus(this.root);
if (!this.options.skipInitialFocus) {
this.focusInitialElement(focusableEls, this.options.initialFocusEl);
}
};
/**
* Releases focus from `root`. Also restores focus to the previously focused
* element.
*/
FocusTrap.prototype.releaseFocus = function () {
[].slice.call(this.root.querySelectorAll("." + FOCUS_SENTINEL_CLASS))
.forEach(function (sentinelEl) {
sentinelEl.parentElement.removeChild(sentinelEl);
});
if (!this.options.skipRestoreFocus && this.elFocusedBeforeTrapFocus) {
this.elFocusedBeforeTrapFocus.focus();
}
};
/**
* Wraps tab focus within `el` by adding two hidden sentinel divs which are
* used to mark the beginning and the end of the tabbable region. When
* focused, these sentinel elements redirect focus to the first/last
* children elements of the tabbable region, ensuring that focus is trapped
* within that region.
*/
FocusTrap.prototype.wrapTabFocus = function (el) {
var _this = this;
var sentinelStart = this.createSentinel();
var sentinelEnd = this.createSentinel();
sentinelStart.addEventListener('focus', function () {
var focusableEls = _this.getFocusableElements(el);
if (focusableEls.length > 0) {
focusableEls[focusableEls.length - 1].focus();
}
});
sentinelEnd.addEventListener('focus', function () {
var focusableEls = _this.getFocusableElements(el);
if (focusableEls.length > 0) {
focusableEls[0].focus();
}
});
el.insertBefore(sentinelStart, el.children[0]);
el.appendChild(sentinelEnd);
};
/**
* Focuses on `initialFocusEl` if defined and a child of the root element.
* Otherwise, focuses on the first focusable child element of the root.
*/
FocusTrap.prototype.focusInitialElement = function (focusableEls, initialFocusEl) {
var focusIndex = 0;
if (initialFocusEl) {
focusIndex = Math.max(focusableEls.indexOf(initialFocusEl), 0);
}
focusableEls[focusIndex].focus();
};
FocusTrap.prototype.getFocusableElements = function (root) {
var focusableEls = [].slice.call(root.querySelectorAll('[autofocus], [tabindex], a, input, textarea, select, button'));
return focusableEls.filter(function (el) {
var isDisabledOrHidden = el.getAttribute('aria-disabled') === 'true' ||
el.getAttribute('disabled') != null ||
el.getAttribute('hidden') != null ||
el.getAttribute('aria-hidden') === 'true';
var isTabbableAndVisible = el.tabIndex >= 0 &&
el.getBoundingClientRect().width > 0 &&
!el.classList.contains(FOCUS_SENTINEL_CLASS) && !isDisabledOrHidden;
var isProgrammaticallyHidden = false;
if (isTabbableAndVisible) {
var style = getComputedStyle(el);
isProgrammaticallyHidden =
style.display === 'none' || style.visibility === 'hidden';
}
return isTabbableAndVisible && !isProgrammaticallyHidden;
});
};
FocusTrap.prototype.createSentinel = function () {
var sentinel = document.createElement('div');
sentinel.setAttribute('tabindex', '0');
// Don't announce in screen readers.
sentinel.setAttribute('aria-hidden', 'true');
sentinel.classList.add(FOCUS_SENTINEL_CLASS);
return sentinel;
};
return FocusTrap;
}());
export { FocusTrap };
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