scrollspy.js
/**
* --------------------------------------------------------------------------
* Bootstrap (v5.0.0-alpha1): scrollspy.js
* Licensed under MIT (https://github.com/twbs/bootstrap/blob/main/LICENSE)
* --------------------------------------------------------------------------
*/
import {
getjQuery,
getSelectorFromElement,
getUID,
isElement,
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 = 'scrollspy'
const VERSION = '5.0.0-alpha1'
const DATA_KEY = 'bs.scrollspy'
const EVENT_KEY = `.${DATA_KEY}`
const DATA_API_KEY = '.data-api'
const Default = {
offset: 10,
method: 'auto',
target: ''
}
const DefaultType = {
offset: 'number',
method: 'string',
target: '(string|element)'
}
const EVENT_ACTIVATE = `activate${EVENT_KEY}`
const EVENT_SCROLL = `scroll${EVENT_KEY}`
const EVENT_LOAD_DATA_API = `load${EVENT_KEY}${DATA_API_KEY}`
const CLASS_NAME_DROPDOWN_ITEM = 'dropdown-item'
const CLASS_NAME_ACTIVE = 'active'
const SELECTOR_DATA_SPY = '[data-spy="scroll"]'
const SELECTOR_NAV_LIST_GROUP = '.nav, .list-group'
const SELECTOR_NAV_LINKS = '.nav-link'
const SELECTOR_NAV_ITEMS = '.nav-item'
const SELECTOR_LIST_ITEMS = '.list-group-item'
const SELECTOR_DROPDOWN = '.dropdown'
const SELECTOR_DROPDOWN_TOGGLE = '.dropdown-toggle'
const METHOD_OFFSET = 'offset'
const METHOD_POSITION = 'position'
/**
* ------------------------------------------------------------------------
* Class Definition
* ------------------------------------------------------------------------
*/
class ScrollSpy {
constructor(element, config) {
this._element = element
this._scrollElement = element.tagName === 'BODY' ? window : element
this._config = this._getConfig(config)
this._selector = `${this._config.target} ${SELECTOR_NAV_LINKS}, ${this._config.target} ${SELECTOR_LIST_ITEMS}, ${this._config.target} .${CLASS_NAME_DROPDOWN_ITEM}`
this._offsets = []
this._targets = []
this._activeTarget = null
this._scrollHeight = 0
EventHandler.on(this._scrollElement, EVENT_SCROLL, event => this._process(event))
this.refresh()
this._process()
Data.setData(element, DATA_KEY, this)
}
// Getters
static get VERSION() {
return VERSION
}
static get Default() {
return Default
}
// Public
refresh() {
const autoMethod = this._scrollElement === this._scrollElement.window ?
METHOD_OFFSET :
METHOD_POSITION
const offsetMethod = this._config.method === 'auto' ?
autoMethod :
this._config.method
const offsetBase = offsetMethod === METHOD_POSITION ?
this._getScrollTop() :
0
this._offsets = []
this._targets = []
this._scrollHeight = this._getScrollHeight()
const targets = SelectorEngine.find(this._selector)
targets.map(element => {
const targetSelector = getSelectorFromElement(element)
const target = targetSelector ? SelectorEngine.findOne(targetSelector) : null
if (target) {
const targetBCR = target.getBoundingClientRect()
if (targetBCR.width || targetBCR.height) {
return [
Manipulator[offsetMethod](target).top + offsetBase,
targetSelector
]
}
}
return null
})
.filter(item => item)
.sort((a, b) => a[0] - b[0])
.forEach(item => {
this._offsets.push(item[0])
this._targets.push(item[1])
})
}
dispose() {
Data.removeData(this._element, DATA_KEY)
EventHandler.off(this._scrollElement, EVENT_KEY)
this._element = null
this._scrollElement = null
this._config = null
this._selector = null
this._offsets = null
this._targets = null
this._activeTarget = null
this._scrollHeight = null
}
// Private
_getConfig(config) {
config = {
...Default,
...(typeof config === 'object' && config ? config : {})
}
if (typeof config.target !== 'string' && isElement(config.target)) {
let { id } = config.target
if (!id) {
id = getUID(NAME)
config.target.id = id
}
config.target = `#${id}`
}
typeCheckConfig(NAME, config, DefaultType)
return config
}
_getScrollTop() {
return this._scrollElement === window ?
this._scrollElement.pageYOffset :
this._scrollElement.scrollTop
}
_getScrollHeight() {
return this._scrollElement.scrollHeight || Math.max(
document.body.scrollHeight,
document.documentElement.scrollHeight
)
}
_getOffsetHeight() {
return this._scrollElement === window ?
window.innerHeight :
this._scrollElement.getBoundingClientRect().height
}
_process() {
const scrollTop = this._getScrollTop() + this._config.offset
const scrollHeight = this._getScrollHeight()
const maxScroll = this._config.offset +
scrollHeight -
this._getOffsetHeight()
if (this._scrollHeight !== scrollHeight) {
this.refresh()
}
if (scrollTop >= maxScroll) {
const target = this._targets[this._targets.length - 1]
if (this._activeTarget !== target) {
this._activate(target)
}
return
}
if (this._activeTarget && scrollTop < this._offsets[0] && this._offsets[0] > 0) {
this._activeTarget = null
this._clear()
return
}
for (let i = this._offsets.length; i--;) {
const isActiveTarget = this._activeTarget !== this._targets[i] &&
scrollTop >= this._offsets[i] &&
(typeof this._offsets[i + 1] === 'undefined' ||
scrollTop < this._offsets[i + 1])
if (isActiveTarget) {
this._activate(this._targets[i])
}
}
}
_activate(target) {
this._activeTarget = target
this._clear()
const queries = this._selector.split(',')
.map(selector => `${selector}[data-target="${target}"],${selector}[href="${target}"]`)
const link = SelectorEngine.findOne(queries.join(','))
if (link.classList.contains(CLASS_NAME_DROPDOWN_ITEM)) {
SelectorEngine.findOne(SELECTOR_DROPDOWN_TOGGLE, link.closest(SELECTOR_DROPDOWN))
.classList.add(CLASS_NAME_ACTIVE)
link.classList.add(CLASS_NAME_ACTIVE)
} else {
// Set triggered link as active
link.classList.add(CLASS_NAME_ACTIVE)
SelectorEngine.parents(link, SELECTOR_NAV_LIST_GROUP)
.forEach(listGroup => {
// Set triggered links parents as active
// With both <ul> and <nav> markup a parent is the previous sibling of any nav ancestor
SelectorEngine.prev(listGroup, `${SELECTOR_NAV_LINKS}, ${SELECTOR_LIST_ITEMS}`)
.forEach(item => item.classList.add(CLASS_NAME_ACTIVE))
// Handle special case when .nav-link is inside .nav-item
SelectorEngine.prev(listGroup, SELECTOR_NAV_ITEMS)
.forEach(navItem => {
SelectorEngine.children(navItem, SELECTOR_NAV_LINKS)
.forEach(item => item.classList.add(CLASS_NAME_ACTIVE))
})
})
}
EventHandler.trigger(this._scrollElement, EVENT_ACTIVATE, {
relatedTarget: target
})
}
_clear() {
SelectorEngine.find(this._selector)
.filter(node => node.classList.contains(CLASS_NAME_ACTIVE))
.forEach(node => node.classList.remove(CLASS_NAME_ACTIVE))
}
// Static
static jQueryInterface(config) {
return this.each(function () {
let data = Data.getData(this, DATA_KEY)
const _config = typeof config === 'object' && config
if (!data) {
data = new ScrollSpy(this, _config)
}
if (typeof config === 'string') {
if (typeof data[config] === 'undefined') {
throw new TypeError(`No method named "${config}"`)
}
data[config]()
}
})
}
static getInstance(element) {
return Data.getData(element, DATA_KEY)
}
}
/**
* ------------------------------------------------------------------------
* Data Api implementation
* ------------------------------------------------------------------------
*/
EventHandler.on(window, EVENT_LOAD_DATA_API, () => {
SelectorEngine.find(SELECTOR_DATA_SPY)
.forEach(spy => new ScrollSpy(spy, Manipulator.getDataAttributes(spy)))
})
const $ = getjQuery()
/**
* ------------------------------------------------------------------------
* jQuery
* ------------------------------------------------------------------------
*/
/* istanbul ignore if */
if ($) {
const JQUERY_NO_CONFLICT = $.fn[NAME]
$.fn[NAME] = ScrollSpy.jQueryInterface
$.fn[NAME].Constructor = ScrollSpy
$.fn[NAME].noConflict = () => {
$.fn[NAME] = JQUERY_NO_CONFLICT
return ScrollSpy.jQueryInterface
}
}
export default ScrollSpy