mirror of
https://github.com/twbs/bootstrap.git
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165 lines
4.8 KiB
JavaScript
165 lines
4.8 KiB
JavaScript
/* ========================================================================
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* Bootstrap: affix.js v3.4.0
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* https://getbootstrap.com/docs/3.4/javascript/#affix
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* ========================================================================
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* Copyright 2011-2019 Twitter, Inc.
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* Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
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* ======================================================================== */
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+function ($) {
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'use strict';
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// AFFIX CLASS DEFINITION
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// ======================
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var Affix = function (element, options) {
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this.options = $.extend({}, Affix.DEFAULTS, options)
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var target = this.options.target === Affix.DEFAULTS.target ? $(this.options.target) : $(document).find(this.options.target)
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this.$target = target
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.on('scroll.bs.affix.data-api', $.proxy(this.checkPosition, this))
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.on('click.bs.affix.data-api', $.proxy(this.checkPositionWithEventLoop, this))
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this.$element = $(element)
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this.affixed = null
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this.unpin = null
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this.pinnedOffset = null
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this.checkPosition()
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}
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Affix.VERSION = '3.4.0'
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Affix.RESET = 'affix affix-top affix-bottom'
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Affix.DEFAULTS = {
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offset: 0,
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target: window
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}
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Affix.prototype.getState = function (scrollHeight, height, offsetTop, offsetBottom) {
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var scrollTop = this.$target.scrollTop()
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var position = this.$element.offset()
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var targetHeight = this.$target.height()
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if (offsetTop != null && this.affixed == 'top') return scrollTop < offsetTop ? 'top' : false
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if (this.affixed == 'bottom') {
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if (offsetTop != null) return (scrollTop + this.unpin <= position.top) ? false : 'bottom'
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return (scrollTop + targetHeight <= scrollHeight - offsetBottom) ? false : 'bottom'
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}
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var initializing = this.affixed == null
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var colliderTop = initializing ? scrollTop : position.top
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var colliderHeight = initializing ? targetHeight : height
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if (offsetTop != null && scrollTop <= offsetTop) return 'top'
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if (offsetBottom != null && (colliderTop + colliderHeight >= scrollHeight - offsetBottom)) return 'bottom'
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return false
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}
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Affix.prototype.getPinnedOffset = function () {
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if (this.pinnedOffset) return this.pinnedOffset
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this.$element.removeClass(Affix.RESET).addClass('affix')
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var scrollTop = this.$target.scrollTop()
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var position = this.$element.offset()
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return (this.pinnedOffset = position.top - scrollTop)
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}
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Affix.prototype.checkPositionWithEventLoop = function () {
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setTimeout($.proxy(this.checkPosition, this), 1)
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}
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Affix.prototype.checkPosition = function () {
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if (!this.$element.is(':visible')) return
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var height = this.$element.height()
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var offset = this.options.offset
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var offsetTop = offset.top
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var offsetBottom = offset.bottom
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var scrollHeight = Math.max($(document).height(), $(document.body).height())
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if (typeof offset != 'object') offsetBottom = offsetTop = offset
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if (typeof offsetTop == 'function') offsetTop = offset.top(this.$element)
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if (typeof offsetBottom == 'function') offsetBottom = offset.bottom(this.$element)
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var affix = this.getState(scrollHeight, height, offsetTop, offsetBottom)
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if (this.affixed != affix) {
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if (this.unpin != null) this.$element.css('top', '')
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var affixType = 'affix' + (affix ? '-' + affix : '')
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var e = $.Event(affixType + '.bs.affix')
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this.$element.trigger(e)
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if (e.isDefaultPrevented()) return
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this.affixed = affix
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this.unpin = affix == 'bottom' ? this.getPinnedOffset() : null
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this.$element
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.removeClass(Affix.RESET)
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.addClass(affixType)
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.trigger(affixType.replace('affix', 'affixed') + '.bs.affix')
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}
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if (affix == 'bottom') {
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this.$element.offset({
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top: scrollHeight - height - offsetBottom
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})
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}
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}
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// AFFIX PLUGIN DEFINITION
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// =======================
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function Plugin(option) {
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return this.each(function () {
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var $this = $(this)
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var data = $this.data('bs.affix')
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var options = typeof option == 'object' && option
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if (!data) $this.data('bs.affix', (data = new Affix(this, options)))
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if (typeof option == 'string') data[option]()
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})
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}
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var old = $.fn.affix
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$.fn.affix = Plugin
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$.fn.affix.Constructor = Affix
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// AFFIX NO CONFLICT
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// =================
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$.fn.affix.noConflict = function () {
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$.fn.affix = old
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return this
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}
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// AFFIX DATA-API
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// ==============
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$(window).on('load', function () {
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$('[data-spy="affix"]').each(function () {
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var $spy = $(this)
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var data = $spy.data()
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data.offset = data.offset || {}
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if (data.offsetBottom != null) data.offset.bottom = data.offsetBottom
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if (data.offsetTop != null) data.offset.top = data.offsetTop
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Plugin.call($spy, data)
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})
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})
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}(jQuery);
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