ec8da8f12c
Co-authored-by: Mikhail Bashkirov <mikhail.bashkirov@ing.com> Co-authored-by: Thijs Louisse <thijs.louisse@ing.com> Co-authored-by: Joren Broekema <joren.broekema@ing.com> Co-authored-by: Gerjan van Geest <gerjan.van.geest@ing.com> Co-authored-by: Erik Kroes <erik.kroes@ing.com> Co-authored-by: Lars den Bakker <lars.den.bakker@ing.com>
58 lines
1.6 KiB
JavaScript
58 lines
1.6 KiB
JavaScript
/**
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* Implementation based on:
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* https://github.com/PolymerElements/iron-overlay-behavior/blob/master/iron-focusables-helper.html
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* The original implementation does not work for non-Polymer web components, and contains several
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* bugs on IE11.
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*/
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/**
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* @param {HTMLElement} a
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* @param {HTMLElement} b
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* @returns {Boolean}
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*/
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function hasLowerTabOrder(a, b) {
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// Normalize tabIndexes
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// e.g. in Firefox `<div contenteditable>` has `tabIndex = -1`
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const ati = Math.max(a.tabIndex, 0);
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const bti = Math.max(b.tabIndex, 0);
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return ati === 0 || bti === 0 ? bti > ati : ati > bti;
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}
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/**
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* @param {HTMLElement[]} left
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* @param {HTMLElement[]} right
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* @returns {HTMLElement[]}
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*/
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function mergeSortByTabIndex(left, right) {
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/** @type {HTMLElement[]} */
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const result = [];
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while (left.length > 0 && right.length > 0) {
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if (hasLowerTabOrder(left[0], right[0])) {
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// @ts-ignore
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result.push(right.shift());
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} else {
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// @ts-ignore
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result.push(left.shift());
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}
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}
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return [...result, ...left, ...right];
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}
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/**
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* @param {HTMLElement[]} elements
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* @returns {HTMLElement[]}
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*/
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export function sortByTabIndex(elements) {
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// Implement a merge sort as Array.prototype.sort does a non-stable sort
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// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort
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const len = elements.length;
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if (len < 2) {
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return elements;
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}
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const pivot = Math.ceil(len / 2);
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const left = sortByTabIndex(elements.slice(0, pivot));
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const right = sortByTabIndex(elements.slice(pivot));
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return mergeSortByTabIndex(left, right);
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}
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