64 lines
1.8 KiB
TypeScript
64 lines
1.8 KiB
TypeScript
/*!
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* Adapted from jQuery UI core
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*
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* http://jqueryui.com
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*
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* Copyright 2014 jQuery Foundation and other contributors
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* Released under the MIT license.
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* http://jquery.org/license
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*
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* http://api.jqueryui.com/category/ui-core/
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*/
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const tabbableNode = /input|select|textarea|button|object/
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function hidesContents(element: HTMLElement) {
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const zeroSize = element.offsetWidth <= 0 && element.offsetHeight <= 0
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// If the node is empty, this is good enough
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if (zeroSize && !element.innerHTML) return true
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// Otherwise we need to check some styles
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const style = window.getComputedStyle(element)
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return (
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style.getPropertyValue("display") === "none" ||
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(zeroSize && style.getPropertyValue("overflow") !== "visible")
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)
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}
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function visible(element: any) {
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let parentElement = element
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while (parentElement) {
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if (parentElement === document.body) break
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if (hidesContents(parentElement)) return false
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parentElement = parentElement.parentNode
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}
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return true
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}
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export function focusable(element: HTMLElement, isTabIndexNotNaN: boolean) {
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const nodeName = element.nodeName.toLowerCase()
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const res =
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//@ts-ignore
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(tabbableNode.test(nodeName) && !element.disabled) ||
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//@ts-ignore
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(nodeName === "a" ? element.href || isTabIndexNotNaN : isTabIndexNotNaN)
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return res && visible(element)
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}
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export function tabbable(element: HTMLElement) {
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let tabIndex = element.getAttribute("tabindex")
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//@ts-ignore
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if (tabIndex === null) tabIndex = undefined
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//@ts-ignore
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const isTabIndexNaN = isNaN(tabIndex)
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//@ts-ignore
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return (isTabIndexNaN || tabIndex >= 0) && focusable(element, !isTabIndexNaN)
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}
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export default function findTabbableDescendants(
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element: HTMLElement
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): HTMLElement[] {
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return [].slice.call(element.querySelectorAll("*"), 0).filter(tabbable)
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}
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