twbs/bootstrap

View on GitHub
js/src/carousel.js

Summary

Maintainability
F
1 wk
Test Coverage
/**
 * --------------------------------------------------------------------------
 * Bootstrap (v4.3.1): carousel.js
 * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
 * --------------------------------------------------------------------------
 */

import {
  jQuery as $,
  TRANSITION_END,
  emulateTransitionEnd,
  getSelectorFromElement,
  getTransitionDurationFromElement,
  isVisible,
  makeArray,
  reflow,
  triggerTransitionEnd,
  typeCheckConfig
} from './util/index'
import Data from './dom/data'
import EventHandler from './dom/event-handler'
import Manipulator from './dom/manipulator'
import SelectorEngine from './dom/selector-engine'

/**
 * ------------------------------------------------------------------------
 * Constants
 * ------------------------------------------------------------------------
 */

const NAME = 'carousel'
const VERSION = '4.3.1'
const DATA_KEY = 'bs.carousel'
const EVENT_KEY = `.${DATA_KEY}`
const DATA_API_KEY = '.data-api'
const ARROW_LEFT_KEYCODE = 37 // KeyboardEvent.which value for left arrow key
const ARROW_RIGHT_KEYCODE = 39 // KeyboardEvent.which value for right arrow key
const TOUCHEVENT_COMPAT_WAIT = 500 // Time for mouse compat events to fire after touch
const SWIPE_THRESHOLD = 40

const Default = {
  interval: 5000,
  keyboard: true,
  slide: false,
  pause: 'hover',
  wrap: true,
  touch: true
}

const DefaultType = {
  interval: '(number|boolean)',
  keyboard: 'boolean',
  slide: '(boolean|string)',
  pause: '(string|boolean)',
  wrap: 'boolean',
  touch: 'boolean'
}

const Direction = {
  NEXT: 'next',
  PREV: 'prev',
  LEFT: 'left',
  RIGHT: 'right'
}

const Event = {
  SLIDE: `slide${EVENT_KEY}`,
  SLID: `slid${EVENT_KEY}`,
  KEYDOWN: `keydown${EVENT_KEY}`,
  MOUSEENTER: `mouseenter${EVENT_KEY}`,
  MOUSELEAVE: `mouseleave${EVENT_KEY}`,
  TOUCHSTART: `touchstart${EVENT_KEY}`,
  TOUCHMOVE: `touchmove${EVENT_KEY}`,
  TOUCHEND: `touchend${EVENT_KEY}`,
  POINTERDOWN: `pointerdown${EVENT_KEY}`,
  POINTERUP: `pointerup${EVENT_KEY}`,
  DRAG_START: `dragstart${EVENT_KEY}`,
  LOAD_DATA_API: `load${EVENT_KEY}${DATA_API_KEY}`,
  CLICK_DATA_API: `click${EVENT_KEY}${DATA_API_KEY}`
}

const ClassName = {
  CAROUSEL: 'carousel',
  ACTIVE: 'active',
  SLIDE: 'slide',
  RIGHT: 'carousel-item-right',
  LEFT: 'carousel-item-left',
  NEXT: 'carousel-item-next',
  PREV: 'carousel-item-prev',
  ITEM: 'carousel-item',
  POINTER_EVENT: 'pointer-event'
}

const Selector = {
  ACTIVE: '.active',
  ACTIVE_ITEM: '.active.carousel-item',
  ITEM: '.carousel-item',
  ITEM_IMG: '.carousel-item img',
  NEXT_PREV: '.carousel-item-next, .carousel-item-prev',
  INDICATORS: '.carousel-indicators',
  DATA_SLIDE: '[data-slide], [data-slide-to]',
  DATA_RIDE: '[data-ride="carousel"]'
}

const PointerType = {
  TOUCH: 'touch',
  PEN: 'pen'
}

/**
 * ------------------------------------------------------------------------
 * Class Definition
 * ------------------------------------------------------------------------
 */
class Carousel {
  constructor(element, config) {
    this._items = null
    this._interval = null
    this._activeElement = null
    this._isPaused = false
    this._isSliding = false
    this.touchTimeout = null
    this.touchStartX = 0
    this.touchDeltaX = 0

    this._config = this._getConfig(config)
    this._element = element
    this._indicatorsElement = SelectorEngine.findOne(Selector.INDICATORS, this._element)
    this._touchSupported = 'ontouchstart' in document.documentElement || navigator.maxTouchPoints > 0
    this._pointerEvent = Boolean(window.PointerEvent || window.MSPointerEvent)

    this._addEventListeners()
    Data.setData(element, DATA_KEY, this)
  }

  // Getters

  static get VERSION() {
    return VERSION
  }

  static get Default() {
    return Default
  }

  // Public

  next() {
    if (!this._isSliding) {
      this._slide(Direction.NEXT)
    }
  }

  nextWhenVisible() {
    // Don't call next when the page isn't visible
    // or the carousel or its parent isn't visible
    if (!document.hidden && isVisible(this._element)) {
      this.next()
    }
  }

  prev() {
    if (!this._isSliding) {
      this._slide(Direction.PREV)
    }
  }

  pause(event) {
    if (!event) {
      this._isPaused = true
    }

    if (SelectorEngine.findOne(Selector.NEXT_PREV, this._element)) {
      triggerTransitionEnd(this._element)
      this.cycle(true)
    }

    clearInterval(this._interval)
    this._interval = null
  }

  cycle(event) {
    if (!event) {
      this._isPaused = false
    }

    if (this._interval) {
      clearInterval(this._interval)
      this._interval = null
    }

    if (this._config && this._config.interval && !this._isPaused) {
      this._interval = setInterval(
        (document.visibilityState ? this.nextWhenVisible : this.next).bind(this),
        this._config.interval
      )
    }
  }

  to(index) {
    this._activeElement = SelectorEngine.findOne(Selector.ACTIVE_ITEM, this._element)
    const activeIndex = this._getItemIndex(this._activeElement)

    if (index > this._items.length - 1 || index < 0) {
      return
    }

    if (this._isSliding) {
      EventHandler.one(this._element, Event.SLID, () => this.to(index))
      return
    }

    if (activeIndex === index) {
      this.pause()
      this.cycle()
      return
    }

    const direction = index > activeIndex ?
      Direction.NEXT :
      Direction.PREV

    this._slide(direction, this._items[index])
  }

  dispose() {
    EventHandler.off(this._element, EVENT_KEY)
    Data.removeData(this._element, DATA_KEY)

    this._items = null
    this._config = null
    this._element = null
    this._interval = null
    this._isPaused = null
    this._isSliding = null
    this._activeElement = null
    this._indicatorsElement = null
  }

  // Private

  _getConfig(config) {
    config = {
      ...Default,
      ...config
    }
    typeCheckConfig(NAME, config, DefaultType)
    return config
  }

  _handleSwipe() {
    const absDeltax = Math.abs(this.touchDeltaX)

    if (absDeltax <= SWIPE_THRESHOLD) {
      return
    }

    const direction = absDeltax / this.touchDeltaX

    this.touchDeltaX = 0

    // swipe left
    if (direction > 0) {
      this.prev()
    }

    // swipe right
    if (direction < 0) {
      this.next()
    }
  }

  _addEventListeners() {
    if (this._config.keyboard) {
      EventHandler
        .on(this._element, Event.KEYDOWN, event => this._keydown(event))
    }

    if (this._config.pause === 'hover') {
      EventHandler
        .on(this._element, Event.MOUSEENTER, event => this.pause(event))
      EventHandler
        .on(this._element, Event.MOUSELEAVE, event => this.cycle(event))
    }

    if (this._config.touch) {
      this._addTouchEventListeners()
    }
  }

  _addTouchEventListeners() {
    if (!this._touchSupported) {
      return
    }

    const start = event => {
      if (this._pointerEvent && PointerType[event.pointerType.toUpperCase()]) {
        this.touchStartX = event.clientX
      } else if (!this._pointerEvent) {
        this.touchStartX = event.touches[0].clientX
      }
    }

    const move = event => {
      // ensure swiping with one touch and not pinching
      if (event.touches && event.touches.length > 1) {
        this.touchDeltaX = 0
      } else {
        this.touchDeltaX = event.touches[0].clientX - this.touchStartX
      }
    }

    const end = event => {
      if (this._pointerEvent && PointerType[event.pointerType.toUpperCase()]) {
        this.touchDeltaX = event.clientX - this.touchStartX
      }

      this._handleSwipe()
      if (this._config.pause === 'hover') {
        // If it's a touch-enabled device, mouseenter/leave are fired as
        // part of the mouse compatibility events on first tap - the carousel
        // would stop cycling until user tapped out of it;
        // here, we listen for touchend, explicitly pause the carousel
        // (as if it's the second time we tap on it, mouseenter compat event
        // is NOT fired) and after a timeout (to allow for mouse compatibility
        // events to fire) we explicitly restart cycling

        this.pause()
        if (this.touchTimeout) {
          clearTimeout(this.touchTimeout)
        }

        this.touchTimeout = setTimeout(event => this.cycle(event), TOUCHEVENT_COMPAT_WAIT + this._config.interval)
      }
    }

    makeArray(SelectorEngine.find(Selector.ITEM_IMG, this._element)).forEach(itemImg => {
      EventHandler.on(itemImg, Event.DRAG_START, e => e.preventDefault())
    })

    if (this._pointerEvent) {
      EventHandler.on(this._element, Event.POINTERDOWN, event => start(event))
      EventHandler.on(this._element, Event.POINTERUP, event => end(event))

      this._element.classList.add(ClassName.POINTER_EVENT)
    } else {
      EventHandler.on(this._element, Event.TOUCHSTART, event => start(event))
      EventHandler.on(this._element, Event.TOUCHMOVE, event => move(event))
      EventHandler.on(this._element, Event.TOUCHEND, event => end(event))
    }
  }

  _keydown(event) {
    if (/input|textarea/i.test(event.target.tagName)) {
      return
    }

    switch (event.which) {
      case ARROW_LEFT_KEYCODE:
        event.preventDefault()
        this.prev()
        break
      case ARROW_RIGHT_KEYCODE:
        event.preventDefault()
        this.next()
        break
      default:
    }
  }

  _getItemIndex(element) {
    this._items = element && element.parentNode ?
      makeArray(SelectorEngine.find(Selector.ITEM, element.parentNode)) :
      []

    return this._items.indexOf(element)
  }

  _getItemByDirection(direction, activeElement) {
    const isNextDirection = direction === Direction.NEXT
    const isPrevDirection = direction === Direction.PREV
    const activeIndex = this._getItemIndex(activeElement)
    const lastItemIndex = this._items.length - 1
    const isGoingToWrap = isPrevDirection && activeIndex === 0 ||
                            isNextDirection && activeIndex === lastItemIndex

    if (isGoingToWrap && !this._config.wrap) {
      return activeElement
    }

    const delta = direction === Direction.PREV ? -1 : 1
    const itemIndex = (activeIndex + delta) % this._items.length

    return itemIndex === -1 ?
      this._items[this._items.length - 1] :
      this._items[itemIndex]
  }

  _triggerSlideEvent(relatedTarget, eventDirectionName) {
    const targetIndex = this._getItemIndex(relatedTarget)
    const fromIndex = this._getItemIndex(SelectorEngine.findOne(Selector.ACTIVE_ITEM, this._element))

    return EventHandler.trigger(this._element, Event.SLIDE, {
      relatedTarget,
      direction: eventDirectionName,
      from: fromIndex,
      to: targetIndex
    })
  }

  _setActiveIndicatorElement(element) {
    if (this._indicatorsElement) {
      const indicators = SelectorEngine.find(Selector.ACTIVE, this._indicatorsElement)
      for (let i = 0; i < indicators.length; i++) {
        indicators[i].classList.remove(ClassName.ACTIVE)
      }

      const nextIndicator = this._indicatorsElement.children[
        this._getItemIndex(element)
      ]

      if (nextIndicator) {
        nextIndicator.classList.add(ClassName.ACTIVE)
      }
    }
  }

  _slide(direction, element) {
    const activeElement = SelectorEngine.findOne(Selector.ACTIVE_ITEM, this._element)
    const activeElementIndex = this._getItemIndex(activeElement)
    const nextElement = element || activeElement &&
      this._getItemByDirection(direction, activeElement)

    const nextElementIndex = this._getItemIndex(nextElement)
    const isCycling = Boolean(this._interval)

    let directionalClassName
    let orderClassName
    let eventDirectionName

    if (direction === Direction.NEXT) {
      directionalClassName = ClassName.LEFT
      orderClassName = ClassName.NEXT
      eventDirectionName = Direction.LEFT
    } else {
      directionalClassName = ClassName.RIGHT
      orderClassName = ClassName.PREV
      eventDirectionName = Direction.RIGHT
    }

    if (nextElement && nextElement.classList.contains(ClassName.ACTIVE)) {
      this._isSliding = false
      return
    }

    const slideEvent = this._triggerSlideEvent(nextElement, eventDirectionName)
    if (slideEvent.defaultPrevented) {
      return
    }

    if (!activeElement || !nextElement) {
      // Some weirdness is happening, so we bail
      return
    }

    this._isSliding = true

    if (isCycling) {
      this.pause()
    }

    this._setActiveIndicatorElement(nextElement)

    if (this._element.classList.contains(ClassName.SLIDE)) {
      nextElement.classList.add(orderClassName)

      reflow(nextElement)

      activeElement.classList.add(directionalClassName)
      nextElement.classList.add(directionalClassName)

      const nextElementInterval = parseInt(nextElement.getAttribute('data-interval'), 10)
      if (nextElementInterval) {
        this._config.defaultInterval = this._config.defaultInterval || this._config.interval
        this._config.interval = nextElementInterval
      } else {
        this._config.interval = this._config.defaultInterval || this._config.interval
      }

      const transitionDuration = getTransitionDurationFromElement(activeElement)

      EventHandler
        .one(activeElement, TRANSITION_END, () => {
          nextElement.classList.remove(directionalClassName)
          nextElement.classList.remove(orderClassName)
          nextElement.classList.add(ClassName.ACTIVE)

          activeElement.classList.remove(ClassName.ACTIVE)
          activeElement.classList.remove(orderClassName)
          activeElement.classList.remove(directionalClassName)

          this._isSliding = false

          setTimeout(() => {
            EventHandler.trigger(this._element, Event.SLID, {
              relatedTarget: nextElement,
              direction: eventDirectionName,
              from: activeElementIndex,
              to: nextElementIndex
            })
          }, 0)
        })

      emulateTransitionEnd(activeElement, transitionDuration)
    } else {
      activeElement.classList.remove(ClassName.ACTIVE)
      nextElement.classList.add(ClassName.ACTIVE)

      this._isSliding = false
      EventHandler.trigger(this._element, Event.SLID, {
        relatedTarget: nextElement,
        direction: eventDirectionName,
        from: activeElementIndex,
        to: nextElementIndex
      })
    }

    if (isCycling) {
      this.cycle()
    }
  }

  // Static

  static _carouselInterface(element, config) {
    let data = Data.getData(element, DATA_KEY)
    let _config = {
      ...Default,
      ...Manipulator.getDataAttributes(element)
    }

    if (typeof config === 'object') {
      _config = {
        ..._config,
        ...config
      }
    }

    const action = typeof config === 'string' ? config : _config.slide

    if (!data) {
      data = new Carousel(element, _config)
    }

    if (typeof config === 'number') {
      data.to(config)
    } else if (typeof action === 'string') {
      if (typeof data[action] === 'undefined') {
        throw new TypeError(`No method named "${action}"`)
      }

      data[action]()
    } else if (_config.interval && _config.ride) {
      data.pause()
      data.cycle()
    }
  }

  static _jQueryInterface(config) {
    return this.each(function () {
      Carousel._carouselInterface(this, config)
    })
  }

  static _dataApiClickHandler(event) {
    const selector = getSelectorFromElement(this)

    if (!selector) {
      return
    }

    const target = SelectorEngine.findOne(selector)

    if (!target || !target.classList.contains(ClassName.CAROUSEL)) {
      return
    }

    const config = {
      ...Manipulator.getDataAttributes(target),
      ...Manipulator.getDataAttributes(this)
    }
    const slideIndex = this.getAttribute('data-slide-to')

    if (slideIndex) {
      config.interval = false
    }

    Carousel._carouselInterface(target, config)

    if (slideIndex) {
      Data.getData(target, DATA_KEY).to(slideIndex)
    }

    event.preventDefault()
  }

  static _getInstance(element) {
    return Data.getData(element, DATA_KEY)
  }
}

/**
 * ------------------------------------------------------------------------
 * Data Api implementation
 * ------------------------------------------------------------------------
 */

EventHandler
  .on(document, Event.CLICK_DATA_API, Selector.DATA_SLIDE, Carousel._dataApiClickHandler)

EventHandler.on(window, Event.LOAD_DATA_API, () => {
  const carousels = makeArray(SelectorEngine.find(Selector.DATA_RIDE))
  for (let i = 0, len = carousels.length; i < len; i++) {
    Carousel._carouselInterface(carousels[i], Data.getData(carousels[i], DATA_KEY))
  }
})

/**
 * ------------------------------------------------------------------------
 * jQuery
 * ------------------------------------------------------------------------
 * add .carousel to jQuery only if jQuery is present
 */

if (typeof $ !== 'undefined') {
  const JQUERY_NO_CONFLICT = $.fn[NAME]
  $.fn[NAME] = Carousel._jQueryInterface
  $.fn[NAME].Constructor = Carousel
  $.fn[NAME].noConflict = () => {
    $.fn[NAME] = JQUERY_NO_CONFLICT
    return Carousel._jQueryInterface
  }
}

export default Carousel