import Keyboard from '../modules/keyboard';
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import DropdownIcon from '../assets/icons/dropdown.svg';
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let optionsCounter = 0;
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function toggleAriaAttribute(element, attribute) {
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element.setAttribute(attribute, !(element.getAttribute(attribute) === 'true'));
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}
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class Picker {
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constructor(select) {
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this.select = select;
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this.container = document.createElement('span');
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this.buildPicker();
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this.select.style.display = 'none';
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this.select.parentNode.insertBefore(this.container, this.select);
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this.label.addEventListener('mousedown', () => {
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this.togglePicker();
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});
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this.label.addEventListener('keydown', (event) => {
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switch(event.keyCode) {
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// Allows the "Enter" key to open the picker
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case Keyboard.keys.ENTER:
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this.togglePicker();
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break;
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// Allows the "Escape" key to close the picker
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case Keyboard.keys.ESCAPE:
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this.escape();
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event.preventDefault();
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break;
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default:
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}
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});
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this.select.addEventListener('change', this.update.bind(this));
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}
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togglePicker() {
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this.container.classList.toggle('ql-expanded');
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// Toggle aria-expanded and aria-hidden to make the picker accessible
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toggleAriaAttribute(this.label, 'aria-expanded');
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toggleAriaAttribute(this.options, 'aria-hidden');
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}
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buildItem(option) {
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let item = document.createElement('span');
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item.tabIndex = '0';
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item.setAttribute('role', 'button');
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item.classList.add('ql-picker-item');
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if (option.hasAttribute('value')) {
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item.setAttribute('data-value', option.getAttribute('value'));
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}
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if (option.textContent) {
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item.setAttribute('data-label', option.textContent);
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}
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item.addEventListener('click', () => {
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this.selectItem(item, true);
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});
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item.addEventListener('keydown', (event) => {
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switch(event.keyCode) {
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// Allows the "Enter" key to select an item
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case Keyboard.keys.ENTER:
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this.selectItem(item, true);
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event.preventDefault();
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break;
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// Allows the "Escape" key to close the picker
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case Keyboard.keys.ESCAPE:
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this.escape();
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event.preventDefault();
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break;
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default:
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}
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});
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return item;
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}
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buildLabel() {
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let label = document.createElement('span');
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label.classList.add('ql-picker-label');
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label.innerHTML = DropdownIcon;
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label.tabIndex = '0';
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label.setAttribute('role', 'button');
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label.setAttribute('aria-expanded', 'false');
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this.container.appendChild(label);
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return label;
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}
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buildOptions() {
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let options = document.createElement('span');
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options.classList.add('ql-picker-options');
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// Don't want screen readers to read this until options are visible
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options.setAttribute('aria-hidden', 'true');
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options.tabIndex = '-1';
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// Need a unique id for aria-controls
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options.id = `ql-picker-options-${optionsCounter}`;
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optionsCounter += 1;
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this.label.setAttribute('aria-controls', options.id);
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this.options = options;
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[].slice.call(this.select.options).forEach((option) => {
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let item = this.buildItem(option);
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options.appendChild(item);
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if (option.selected === true) {
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this.selectItem(item);
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}
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});
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this.container.appendChild(options);
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}
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buildPicker() {
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[].slice.call(this.select.attributes).forEach((item) => {
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this.container.setAttribute(item.name, item.value);
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});
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this.container.classList.add('ql-picker');
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this.label = this.buildLabel();
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this.buildOptions();
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}
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escape() {
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// Close menu and return focus to trigger label
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this.close();
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// Need setTimeout for accessibility to ensure that the browser executes
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// focus on the next process thread and after any DOM content changes
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setTimeout(() => this.label.focus(), 1);
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}
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close() {
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this.container.classList.remove('ql-expanded');
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this.label.setAttribute('aria-expanded', 'false');
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this.options.setAttribute('aria-hidden', 'true');
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}
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selectItem(item, trigger = false) {
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let selected = this.container.querySelector('.ql-selected');
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if (item === selected) return;
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if (selected != null) {
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selected.classList.remove('ql-selected');
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}
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if (item == null) return;
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item.classList.add('ql-selected');
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this.select.selectedIndex = [].indexOf.call(item.parentNode.children, item);
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if (item.hasAttribute('data-value')) {
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this.label.setAttribute('data-value', item.getAttribute('data-value'));
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} else {
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this.label.removeAttribute('data-value');
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}
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if (item.hasAttribute('data-label')) {
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this.label.setAttribute('data-label', item.getAttribute('data-label'));
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} else {
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this.label.removeAttribute('data-label');
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}
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if (trigger) {
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if (typeof Event === 'function') {
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this.select.dispatchEvent(new Event('change'));
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} else if (typeof Event === 'object') { // IE11
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let event = document.createEvent('Event');
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event.initEvent('change', true, true);
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this.select.dispatchEvent(event);
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}
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this.close();
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}
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}
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update() {
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let option;
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if (this.select.selectedIndex > -1) {
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let item = this.container.querySelector('.ql-picker-options').children[this.select.selectedIndex];
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option = this.select.options[this.select.selectedIndex];
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this.selectItem(item);
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} else {
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this.selectItem(null);
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}
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let isActive = option != null && option !== this.select.querySelector('option[selected]');
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this.label.classList.toggle('ql-active', isActive);
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}
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}
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export default Picker;
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