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Revamp tabs & follow ARIA 1.1 practices (#33079)
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* Tab: Revamp tab.js & add support Aria features

* Tab: Add tab support, just to keep backwards compatibility. Better to remove it on v6

* Revert "Tab: Add tab support, just to keep backwards compatibility. Better to remove it on v6"

* Support arrow down/up functionality

* add prevent default to avoid scrolling the page during up/down keys handling

* remove panel tabindex handling

* Expand documentation text for JS plugin

* Rearrange new docs to specifically call out a11y

* properly place section

Co-authored-by: XhmikosR <[email protected]>
Co-authored-by: Patrick H. Lauke <[email protected]>
Co-authored-by: Mark Otto <[email protected]>
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@GeoSot @XhmikosR
@patrickhlauke @mdo
4 people authored Apr 6, 2022
1 parent 238afd9 commit 135b9cd
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281 changes: 197 additions & 84 deletions js/src/tab.js
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@
* --------------------------------------------------------------------------
*/

import { defineJQueryPlugin, getElementFromSelector, isDisabled, reflow } from './util/index'
import { defineJQueryPlugin, getElementFromSelector, getNextActiveElement, isDisabled } from './util/index'
import EventHandler from './dom/event-handler'
import SelectorEngine from './dom/selector-engine'
import BaseComponent from './base-component'
Expand All @@ -17,158 +17,264 @@ import BaseComponent from './base-component'
const NAME = 'tab'
const DATA_KEY = 'bs.tab'
const EVENT_KEY = `.${DATA_KEY}`
const DATA_API_KEY = '.data-api'

const EVENT_HIDE = `hide${EVENT_KEY}`
const EVENT_HIDDEN = `hidden${EVENT_KEY}`
const EVENT_SHOW = `show${EVENT_KEY}`
const EVENT_SHOWN = `shown${EVENT_KEY}`
const EVENT_CLICK_DATA_API = `click${EVENT_KEY}${DATA_API_KEY}`
const EVENT_CLICK_DATA_API = `click${EVENT_KEY}`
const EVENT_KEYDOWN = `keydown${EVENT_KEY}`
const EVENT_LOAD_DATA_API = `load${EVENT_KEY}`

const ARROW_LEFT_KEY = 'ArrowLeft'
const ARROW_RIGHT_KEY = 'ArrowRight'
const ARROW_UP_KEY = 'ArrowUp'
const ARROW_DOWN_KEY = 'ArrowDown'

const CLASS_NAME_DROPDOWN_MENU = 'dropdown-menu'
const CLASS_NAME_ACTIVE = 'active'
const CLASS_NAME_FADE = 'fade'
const CLASS_NAME_SHOW = 'show'
const CLASS_DROPDOWN = 'dropdown'

const SELECTOR_DROPDOWN = '.dropdown'
const SELECTOR_NAV_LIST_GROUP = '.nav, .list-group'
const SELECTOR_ACTIVE = '.active'
const SELECTOR_ACTIVE_UL = ':scope > li > .active'
const SELECTOR_DATA_TOGGLE = '[data-bs-toggle="tab"], [data-bs-toggle="pill"], [data-bs-toggle="list"]'
const SELECTOR_DROPDOWN_TOGGLE = '.dropdown-toggle'
const SELECTOR_DROPDOWN_ACTIVE_CHILD = ':scope > .dropdown-menu .active'
const SELECTOR_DROPDOWN_MENU = '.dropdown-menu'
const SELECTOR_DROPDOWN_ITEM = '.dropdown-item'
const NOT_SELECTOR_DROPDOWN_TOGGLE = ':not(.dropdown-toggle)'

const SELECTOR_TAB_PANEL = '.list-group, .nav, [role="tablist"]'
const SELECTOR_OUTER = '.nav-item, .list-group-item'
const SELECTOR_INNER = `.nav-link${NOT_SELECTOR_DROPDOWN_TOGGLE}, .list-group-item${NOT_SELECTOR_DROPDOWN_TOGGLE}, [role="tab"]${NOT_SELECTOR_DROPDOWN_TOGGLE}`
const SELECTOR_DATA_TOGGLE = '[data-bs-toggle="tab"], [data-bs-toggle="pill"], [data-bs-toggle="list"]' // todo:v6: could be only `tab`
const SELECTOR_INNER_ELEM = `${SELECTOR_INNER}, ${SELECTOR_DATA_TOGGLE}`

const SELECTOR_DATA_TOGGLE_ACTIVE = `.${CLASS_NAME_ACTIVE}[data-bs-toggle="tab"], .${CLASS_NAME_ACTIVE}[data-bs-toggle="pill"], .${CLASS_NAME_ACTIVE}[data-bs-toggle="list"]`

/**
* Class definition
*/

class Tab extends BaseComponent {
constructor(element) {
super(element)
this._parent = this._element.closest(SELECTOR_TAB_PANEL)

if (!this._parent) {
return
// todo: should Throw exception on v6
// throw new TypeError(`${element.outerHTML} has not a valid parent ${SELECTOR_INNER_ELEM}`)
}

// Set up initial aria attributes
this._setInitialAttributes(this._parent, this._getChildren())

EventHandler.on(this._element, EVENT_KEYDOWN, event => this._keydown(event))
}

// Getters
static get NAME() {
return NAME
}

// Public
show() {
if (this._element.parentNode &&
this._element.parentNode.nodeType === Node.ELEMENT_NODE &&
this._element.classList.contains(CLASS_NAME_ACTIVE)) {
show() { // Shows this elem and deactivate the active sibling if exists
const innerElem = this._element
if (this._elemIsActive(innerElem)) {
return
}

const target = getElementFromSelector(this._element)
const listElement = this._element.closest(SELECTOR_NAV_LIST_GROUP)
let previous
// Search for active tab on same parent to deactivate it
const active = this._getActiveElem()

if (listElement) {
const itemSelector = listElement.nodeName === 'UL' || listElement.nodeName === 'OL' ? SELECTOR_ACTIVE_UL : SELECTOR_ACTIVE
previous = SelectorEngine.find(itemSelector, listElement)
previous = previous[previous.length - 1]
}

const hideEvent = previous ?
EventHandler.trigger(previous, EVENT_HIDE, { relatedTarget: this._element }) :
const hideEvent = active ?
EventHandler.trigger(active, EVENT_HIDE, { relatedTarget: innerElem }) :
null

const showEvent = EventHandler.trigger(this._element, EVENT_SHOW, { relatedTarget: previous })
const showEvent = EventHandler.trigger(innerElem, EVENT_SHOW, { relatedTarget: active })

if (showEvent.defaultPrevented || (hideEvent !== null && hideEvent.defaultPrevented)) {
if (showEvent.defaultPrevented || (hideEvent && hideEvent.defaultPrevented)) {
return
}

this._activate(this._element, listElement)
this._deactivate(active, innerElem)
this._activate(innerElem, active)
}

const complete = () => {
EventHandler.trigger(previous, EVENT_HIDDEN, { relatedTarget: this._element })
EventHandler.trigger(this._element, EVENT_SHOWN, { relatedTarget: previous })
// Private
_activate(element, relatedElem) {
if (!element) {
return
}

if (target) {
this._activate(target, target.parentNode, complete)
} else {
complete()
}
}
element.classList.add(CLASS_NAME_ACTIVE)

// Private
_activate(element, container, callback) {
const activeElements = container && (container.nodeName === 'UL' || container.nodeName === 'OL') ?
SelectorEngine.find(SELECTOR_ACTIVE_UL, container) :
SelectorEngine.children(container, SELECTOR_ACTIVE)
this._activate(getElementFromSelector(element)) // Search and activate/show the proper section

const active = activeElements[0]
const isTransitioning = callback && (active && active.classList.contains(CLASS_NAME_FADE))
const isAnimated = element.classList.contains(CLASS_NAME_FADE)
const complete = () => {
if (isAnimated) { // todo: maybe is redundant
element.classList.add(CLASS_NAME_SHOW)
}

const complete = () => this._transitionComplete(element, active, callback)
if (element.getAttribute('role') !== 'tab') {
return
}

if (active && isTransitioning) {
active.classList.remove(CLASS_NAME_SHOW)
this._queueCallback(complete, element, true)
} else {
complete()
element.focus()
element.removeAttribute('tabindex')
element.setAttribute('aria-selected', true)
this._toggleDropDown(element, true)
EventHandler.trigger(element, EVENT_SHOWN, {
relatedTarget: relatedElem
})
}

this._queueCallback(complete, element, isAnimated)
}

_transitionComplete(element, active, callback) {
if (active) {
active.classList.remove(CLASS_NAME_ACTIVE)
_deactivate(element, relatedElem) {
if (!element) {
return
}

element.classList.remove(CLASS_NAME_ACTIVE)
element.blur()

const dropdownChild = SelectorEngine.findOne(SELECTOR_DROPDOWN_ACTIVE_CHILD, active.parentNode)
this._deactivate(getElementFromSelector(element)) // Search and deactivate the shown section too

if (dropdownChild) {
dropdownChild.classList.remove(CLASS_NAME_ACTIVE)
const isAnimated = element.classList.contains(CLASS_NAME_FADE)
const complete = () => {
if (isAnimated) { // todo maybe is redundant
element.classList.remove(CLASS_NAME_SHOW)
}

if (active.getAttribute('role') === 'tab') {
active.setAttribute('aria-selected', false)
if (element.getAttribute('role') !== 'tab') {
return
}

element.setAttribute('aria-selected', false)
element.setAttribute('tabindex', '-1')
this._toggleDropDown(element, false)
EventHandler.trigger(element, EVENT_HIDDEN, { relatedTarget: relatedElem })
}

element.classList.add(CLASS_NAME_ACTIVE)
if (element.getAttribute('role') === 'tab') {
element.setAttribute('aria-selected', true)
this._queueCallback(complete, element, isAnimated)
}

_keydown(event) {
if (!([ARROW_LEFT_KEY, ARROW_RIGHT_KEY, ARROW_UP_KEY, ARROW_DOWN_KEY].includes(event.key))) {
return
}

event.stopPropagation()// stopPropagation/preventDefault both added to support up/down keys without scrolling the page
event.preventDefault()
const isNext = [ARROW_RIGHT_KEY, ARROW_DOWN_KEY].includes(event.key)
const nextActiveElement = getNextActiveElement(this._getChildren(), event.target, isNext, true)
Tab.getOrCreateInstance(nextActiveElement).show()
}

_getChildren() { // collection of inner elements
return SelectorEngine.find(SELECTOR_INNER_ELEM, this._parent)
}

_getActiveElem() {
return this._getChildren().find(child => this._elemIsActive(child)) || null
}

_setInitialAttributes(parent, children) {
this._setAttributeIfNotExists(parent, 'role', 'tablist')

for (const child of children) {
this._setInitialAttributesOnChild(child)
}
}

reflow(element)
_setInitialAttributesOnChild(child) {
child = this._getInnerElement(child)
const isActive = this._elemIsActive(child)
const outerElem = this._getOuterElement(child)
child.setAttribute('aria-selected', isActive)

if (element.classList.contains(CLASS_NAME_FADE)) {
element.classList.add(CLASS_NAME_SHOW)
if (outerElem !== child) {
this._setAttributeIfNotExists(outerElem, 'role', 'presentation')
}

let parent = element.parentNode
if (parent && parent.nodeName === 'LI') {
parent = parent.parentNode
if (!isActive) {
child.setAttribute('tabindex', '-1')
}

if (parent && parent.classList.contains(CLASS_NAME_DROPDOWN_MENU)) {
const dropdownElement = element.closest(SELECTOR_DROPDOWN)
this._setAttributeIfNotExists(child, 'role', 'tab')

if (dropdownElement) {
for (const dropdown of SelectorEngine.find(SELECTOR_DROPDOWN_TOGGLE, dropdownElement)) {
dropdown.classList.add(CLASS_NAME_ACTIVE)
}
}
// set attributes to the related panel too
this._setInitialAttributesOnTargetPanel(child)
}

_setInitialAttributesOnTargetPanel(child) {
const target = getElementFromSelector(child)

element.setAttribute('aria-expanded', true)
if (!target) {
return
}

if (callback) {
callback()
this._setAttributeIfNotExists(target, 'role', 'tabpanel')

if (child.id) {
this._setAttributeIfNotExists(target, 'aria-labelledby', `#${child.id}`)
}
}

_toggleDropDown(element, open) {
const outerElem = this._getOuterElement(element)
if (!outerElem.classList.contains(CLASS_DROPDOWN)) {
return
}

const toggle = (selector, className) => {
const element = SelectorEngine.findOne(selector, outerElem)
if (element) {
element.classList.toggle(className, open)
}
}

toggle(SELECTOR_DROPDOWN_TOGGLE, CLASS_NAME_ACTIVE)
toggle(SELECTOR_DROPDOWN_MENU, CLASS_NAME_SHOW)
toggle(SELECTOR_DROPDOWN_ITEM, CLASS_NAME_ACTIVE)
outerElem.setAttribute('aria-expanded', open)
}

_setAttributeIfNotExists(element, attribute, value) {
if (!element.hasAttribute(attribute)) {
element.setAttribute(attribute, value)
}
}

_elemIsActive(elem) {
return elem.classList.contains(CLASS_NAME_ACTIVE)
}

// Try to get the inner element (usually the .nav-link)
_getInnerElement(elem) {
return elem.matches(SELECTOR_INNER_ELEM) ? elem : SelectorEngine.findOne(SELECTOR_INNER_ELEM, elem)
}

// Try to get the outer element (usually the .nav-item)
_getOuterElement(elem) {
return elem.closest(SELECTOR_OUTER) || elem
}

// Static
static jQueryInterface(config) {
return this.each(function () {
const data = Tab.getOrCreateInstance(this)

if (typeof config === 'string') {
if (typeof data[config] === 'undefined') {
throw new TypeError(`No method named "${config}"`)
}
if (typeof config !== 'string') {
return
}

data[config]()
if (data[config] === undefined || config.startsWith('_') || config === 'constructor') {
throw new TypeError(`No method named "${config}"`)
}

data[config]()
})
}
}
Expand All @@ -186,10 +292,17 @@ EventHandler.on(document, EVENT_CLICK_DATA_API, SELECTOR_DATA_TOGGLE, function (
return
}

const data = Tab.getOrCreateInstance(this)
data.show()
Tab.getOrCreateInstance(this).show()
})

/**
* Initialize on focus
*/
EventHandler.on(window, EVENT_LOAD_DATA_API, () => {
for (const element of SelectorEngine.find(SELECTOR_DATA_TOGGLE_ACTIVE)) {
Tab.getOrCreateInstance(element)
}
})
/**
* jQuery
*/
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