/
ponyfill.ts
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/
ponyfill.ts
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/**
* @license
* Copyright 2018 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.
*/
/**
* @fileoverview A "ponyfill" is a polyfill that doesn't modify the global
* prototype chain. This makes ponyfills safer than traditional polyfills,
* especially for libraries like MDC.
*/
export function closest(element: Element, selector: string): Element|null {
if (element.closest) {
return element.closest(selector);
}
let el: Element|null = element;
while (el) {
if (matches(el, selector)) {
return el;
}
el = el.parentElement;
}
return null;
}
/** Element.matches with support for webkit and IE. */
export function matches(element: Element, selector: string): boolean {
const nativeMatches = element.matches || element.webkitMatchesSelector ||
(element as any).msMatchesSelector;
return nativeMatches.call(element, selector);
}
/**
* Used to compute the estimated scroll width of elements. When an element is
* hidden due to display: none; being applied to a parent element, the width is
* returned as 0. However, the element will have a true width once no longer
* inside a display: none context. This method computes an estimated width when
* the element is hidden or returns the true width when the element is visble.
* @param {Element} element the element whose width to estimate
*/
export function estimateScrollWidth(element: Element): number {
// Check the offsetParent. If the element inherits display: none from any
// parent, the offsetParent property will be null (see
// https://developer.mozilla.org/en-US/docs/Web/API/HTMLElement/offsetParent).
// This check ensures we only clone the node when necessary.
const htmlEl = element as HTMLElement;
if (htmlEl.offsetParent !== null) {
return htmlEl.scrollWidth;
}
const clone = htmlEl.cloneNode(true) as HTMLElement;
clone.style.setProperty('position', 'absolute');
clone.style.setProperty('transform', 'translate(-9999px, -9999px)');
document.documentElement.appendChild(clone);
const scrollWidth = clone.scrollWidth;
document.documentElement.removeChild(clone);
return scrollWidth;
}