carbon-components
Version:
Carbon Components is a component library for IBM Cloud
261 lines (241 loc) • 9.91 kB
JavaScript
/**
* Copyright IBM Corp. 2016, 2018
*
* This source code is licensed under the Apache-2.0 license found in the
* LICENSE file in the root directory of this source tree.
*/
import settings from '../../globals/js/settings';
import mixin from '../../globals/js/misc/mixin';
import createComponent from '../../globals/js/mixins/create-component';
import initComponentBySearch from '../../globals/js/mixins/init-component-by-search';
import trackBlur from '../../globals/js/mixins/track-blur';
import eventMatches from '../../globals/js/misc/event-matches';
import on from '../../globals/js/misc/on';
const toArray = arrayLike => Array.prototype.slice.call(arrayLike);
class Dropdown extends mixin(createComponent, initComponentBySearch, trackBlur) {
/**
* A selector with drop downs.
* @extends CreateComponent
* @extends InitComponentBySearch
* @extends TrackBlur
* @param {HTMLElement} element The element working as a selector.
* @param {Object} [options] The component options.
* @param {string} [options.selectorItem] The CSS selector to find clickable areas in dropdown items.
* @param {string} [options.selectorItemSelected] The CSS selector to find the clickable area in the selected dropdown item.
* @param {string} [options.classSelected] The CSS class for the selected dropdown item.
* @param {string} [options.classOpen] The CSS class for the open state.
* @param {string} [options.classDisabled] The CSS class for the disabled state.
* @param {string} [options.eventBeforeSelected]
* The name of the custom event fired before a drop down item is selected.
* Cancellation of this event stops selection of drop down item.
* @param {string} [options.eventAfterSelected] The name of the custom event fired after a drop down item is selected.
*/
constructor(element, options) {
super(element, options);
this.manage(
on(this.element.ownerDocument, 'click', event => {
this._toggle(event);
})
);
this.manage(
on(this.element, 'keydown', event => {
this._handleKeyDown(event);
})
);
this.manage(
on(this.element, 'click', event => {
const item = eventMatches(event, this.options.selectorItem);
if (item) {
this.select(item);
}
})
);
}
/**
* Handles keydown event.
* @param {Event} event The event triggering this method.
*/
_handleKeyDown(event) {
const isOpen = this.element.classList.contains(this.options.classOpen);
const direction = {
38: this.constructor.NAVIGATE.BACKWARD,
40: this.constructor.NAVIGATE.FORWARD,
}[event.which];
if (isOpen && direction !== undefined) {
this.navigate(direction);
event.preventDefault(); // Prevents up/down keys from scrolling container
} else {
this._toggle(event);
}
}
/**
* Opens and closes the dropdown menu.
* @param {Event} [event] The event triggering this method.
*/
_toggle(event) {
const isDisabled = this.element.classList.contains(this.options.classDisabled);
if (isDisabled) {
return;
}
if (
([13, 32, 40].indexOf(event.which) >= 0 && !event.target.matches(this.options.selectorItem)) ||
event.which === 27 ||
event.type === 'click'
) {
const isOpen = this.element.classList.contains(this.options.classOpen);
const isOfSelf = this.element.contains(event.target);
const actions = {
add: isOfSelf && event.which === 40 && !isOpen,
remove: (!isOfSelf || event.which === 27) && isOpen,
toggle: isOfSelf && event.which !== 27 && event.which !== 40,
};
Object.keys(actions).forEach(action => {
if (actions[action]) {
this.element.classList[action](this.options.classOpen);
this.element.focus();
}
});
const listItems = toArray(this.element.querySelectorAll(this.options.selectorItem));
listItems.forEach(item => {
if (this.element.classList.contains(this.options.classOpen)) {
item.tabIndex = 0;
} else {
item.tabIndex = -1;
}
});
}
}
/**
* @returns {Element} Currently highlighted element.
*/
getCurrentNavigation() {
const focused = this.element.ownerDocument.activeElement;
return focused.nodeType === Node.ELEMENT_NODE && focused.matches(this.options.selectorItem) ? focused : null;
}
/**
* Moves up/down the focus.
* @param {number} direction The direction of navigating.
*/
navigate(direction) {
const items = toArray(this.element.querySelectorAll(this.options.selectorItem));
const start = this.getCurrentNavigation() || this.element.querySelector(this.options.selectorItemSelected);
const getNextItem = old => {
const handleUnderflow = (i, l) => i + (i >= 0 ? 0 : l);
const handleOverflow = (i, l) => i - (i < l ? 0 : l);
// `items.indexOf(old)` may be -1 (Scenario of no previous focus)
const index = Math.max(items.indexOf(old) + direction, -1);
return items[handleUnderflow(handleOverflow(index, items.length), items.length)];
};
for (let current = getNextItem(start); current && current !== start; current = getNextItem(current)) {
if (
!current.matches(this.options.selectorItemHidden) &&
!current.parentNode.matches(this.options.selectorItemHidden) &&
!current.matches(this.options.selectorItemSelected)
) {
current.focus();
break;
}
}
}
/**
* Handles clicking on the dropdown options, doing the following:
* * Change Dropdown text to selected option.
* * Remove selected option from options when selected.
* * Emit custom events.
* @param {HTMLElement} itemToSelect The element to be activated.
*/
select(itemToSelect) {
const eventStart = new CustomEvent(this.options.eventBeforeSelected, {
bubbles: true,
cancelable: true,
detail: { item: itemToSelect },
});
if (this.element.dispatchEvent(eventStart)) {
if (this.element.dataset.dropdownType !== 'navigation') {
const selectorText =
this.element.dataset.dropdownType !== 'inline' ? this.options.selectorText : this.options.selectorTextInner;
const text = this.element.querySelector(selectorText);
if (text) {
text.innerHTML = itemToSelect.innerHTML;
}
itemToSelect.classList.add(this.options.classSelected);
}
this.element.dataset.value = itemToSelect.parentElement.dataset.value;
toArray(this.element.querySelectorAll(this.options.selectorItemSelected)).forEach(item => {
if (itemToSelect !== item) {
item.classList.remove(this.options.classSelected);
}
});
this.element.dispatchEvent(
new CustomEvent(this.options.eventAfterSelected, {
bubbles: true,
cancelable: true,
detail: { item: itemToSelect },
})
);
}
}
/**
* Closes the dropdown menu if this component loses focus.
*/
handleBlur() {
this.element.classList.remove(this.options.classOpen);
}
/**
* The map associating DOM element and selector instance.
* @member Dropdown.components
* @type {WeakMap}
*/
static components /* #__PURE_CLASS_PROPERTY__ */ = new WeakMap();
/**
* The component options.
* If `options` is specified in the constructor, {@linkcode Dropdown.create .create()}, or {@linkcode Dropdown.init .init()},
* properties in this object are overriden for the instance being create and how {@linkcode Dropdown.init .init()} works.
* @member Dropdown.options
* @type {Object}
* @property {string} selectorInit The CSS selector to find selectors.
* @property {string} [selectorText] The CSS selector to find the element showing the selected item.
* @property {string} [selectorTextInner] The CSS selector to find the element showing the selected item, used for inline mode.
* @property {string} [selectorItem] The CSS selector to find clickable areas in dropdown items.
* @property {string} [selectorItemHidden]
* The CSS selector to find hidden dropdown items.
* Used to skip dropdown items for keyboard navigation.
* @property {string} [selectorItemSelected] The CSS selector to find the clickable area in the selected dropdown item.
* @property {string} [classSelected] The CSS class for the selected dropdown item.
* @property {string} [classOpen] The CSS class for the open state.
* @property {string} [classDisabled] The CSS class for the disabled state.
* @property {string} [eventBeforeSelected]
* The name of the custom event fired before a drop down item is selected.
* Cancellation of this event stops selection of drop down item.
* @property {string} [eventAfterSelected] The name of the custom event fired after a drop down item is selected.
*/
static get options() {
const { prefix } = settings;
return {
selectorInit: '[data-dropdown]',
selectorText: `.${prefix}--dropdown-text`,
selectorTextInner: `.${prefix}--dropdown-text__inner`,
selectorItem: `.${prefix}--dropdown-link`,
selectorItemSelected: `.${prefix}--dropdown--selected`,
selectorItemHidden: `[hidden],[aria-hidden="true"]`,
classSelected: `${prefix}--dropdown--selected`,
classOpen: `${prefix}--dropdown--open`,
classDisabled: `${prefix}--dropdown--disabled`,
eventBeforeSelected: 'dropdown-beingselected',
eventAfterSelected: 'dropdown-selected',
};
}
/**
* Enum for navigating backward/forward.
* @readonly
* @member Dropdown.NAVIGATE
* @type {Object}
* @property {number} BACKWARD Navigating backward.
* @property {number} FORWARD Navigating forward.
*/
static NAVIGATE /* #__PURE_CLASS_PROPERTY__ */ = {
BACKWARD: -1,
FORWARD: 1,
};
}
export default Dropdown;