https://archfondas.lt/wp-content/themes/archfondas/js/snapback_cache.js?ver=7.1

1// Example Usage:
2//   var pageCache = SnapbackCache({
3//     bodySelector: "#recordings",
4//   })
5//  
6//   pageCache.markDirty("comment/1")
7//
8// Required options:
9//   * bodySelector: Element to be cached and position saved
10// Optional options:
11//   * finish            Pass function to get things on your page to "finish" that you don't want to cache in an inbetween state. 
12//                       By default we finish jQuery Animations.
13//   * refreshItems      You may mark items dirty in your DOM as things are edited but might still be in the
14//                       page cache, this is a callback for refreshing those dirty items. Using above example
15//                       refreshItems function would be passed arguement ["comment/1"]
16//   * removeAutofocus   Pass function to remove items that cause your page to autofocusing. Autofocus behavior can screw with 
17//                       setting your scroll position. 
18//
19// Events:
20//   * snapback-cache:cached  Triggered when a cache has been set. The cachedPage object is returned with
21//                        the event (triggered on bodySelector)
22//   * snapback-cache:loaded  Triggered when a cache has been loaded. The cachedPage object is returned with
23//                        the event (triggered on bodySelector)
24var SnapbackCache = (function(options) {
25  var options = options || {}
26
27  var SessionStorageHash = (function() {
28    var set = function(namespace, key, item){
29      var storageHash = sessionStorage.getItem(namespace);
30      if (!storageHash) {
31        storageHash = {}
32      } else {
33        storageHash = JSON.parse(storageHash)
34      }
35
36      if (item) {
37        storageHash[key] = JSON.stringify(item)
38      } else {
39        delete storageHash[key]
40      }
41
42      sessionStorage.setItem(namespace, JSON.stringify(storageHash))
43    }
44
45    var get = function(namespace, key, item){
46      var storageHash = sessionStorage.getItem(namespace)
47
48      if(storageHash){
49        storageHash = JSON.parse(storageHash)
50        if(storageHash[key]){
51          return JSON.parse(storageHash[key])
52        }
53      }
54
55      return null
56    }
57
58    return {
59      set: set,
60      get: get
61    }
62  })()
63
64  var enabled = true
65
66  var disable = function() {
67    enabled = false
68  }
69
70  var enable = function () {
71    enabled = true
72  }
73
74  var supported = function(){
75    return !!(sessionStorage && history && enabled)
76  }
77
78  var setItem = function(url, value){
79    if(value){
80      // only keep 10 things cached
81      trimStorage()
82    }
83    SessionStorageHash.set("pageCache", url, value)
84  }
85
86  var getItem = function(url){
87    return SessionStorageHash.get("pageCache", url)
88  }
89
90  var removeItem = function(url){
91    setItem(url, null)
92  }
93
94  var disableAutofocusIfReplacingCachedPage = function(){
95    if(typeof options.removeAutofocus === "function"){
96      if(willUseCacheOnThisPage()){
97        options.removeAutofocus()
98      }
99    }
100  }
101
102  var cachePage = function(filterOut, callbackFunction){
103    if (typeof filterOut === 'function') {
104      callbackFunction = filterOut
105      filterOut = null
106    }
107
108    if (!supported()){
109      if(callbackFunction){
110        callbackFunction()
111      }
112      return;
113    }
114
115    // get jQuery animations to finish
116    jQuery(document).finish()
117    if (typeof options.wait === "function")
118      options.finish()
119
120    // Give transitions/animations a chance to finish
121    setTimeout(function(){
122      if (typeof options.removeAutofocus === "function")
123        options.removeAutofocus()
124
125      var $cachedBody = jQuery(options.bodySelector)
126      if (filterOut) {
127        $cachedBody = $cachedBody.clone().find(filterOut).replaceWith("").end()
128      }
129
130      var cachedPage = {
131        body: $cachedBody.html(),
132        title: document.title,
133        positionY: window.pageYOffset,
134        positionX: window.pageXOffset,
135        cachedAt: new Date().getTime()
136      }
137
138      // help to setup the next page of infinite scrolling
139      if (typeof options.nextPageOffset === "function")
140        cachedPage.nextPageOffset = options.nextPageOffset()
141
142      setItem(document.location.href, cachedPage)
143
144      jQuery(options.bodySelector).trigger("snapback-cache:cached", cachedPage)
145
146      if(callbackFunction){
147        callbackFunction()
148      }
149    }, 10)
150  }
151
152  var loadFromCache = function(noCacheCallback){
153    // Check if there is a cache and if its less than 15 minutes old
154    if(willUseCacheOnThisPage()){
155      var cachedPage = getItem(document.location.href)
156
157      // replace the content and scroll
158      jQuery(options.bodySelector).html(cachedPage.body)
159
160      // try to make sure autofocus events don't run. 
161      if (typeof options.removeAutofocus === "function")
162        options.removeAutofocus()
163
164      // IE 10+ needs a delay to stop the autofocus during dom load
165      setTimeout(function(){
166        window.scrollTo(cachedPage.positionX, cachedPage.positionY)
167      }, 1);
168
169      // pop the cache
170      removeItem(document.location.href)
171
172      jQuery(options.bodySelector).trigger("snapback-cache:loaded", cachedPage)
173
174      // refresh any obsolete recordings in the activity feed
175      var dirties = getDirties()
176      if(dirties){
177        if (typeof options.refreshItems === "function")
178          options.refreshItems(dirties)
179
180        clearDirty()
181      }
182
183      return false;

184    }
185    else{
186      if(noCacheCallback){
187        noCacheCallback()
188      }
189      else{
190        return
191      }
192    }
193  }
194
195  var clearDirty = function() {
196    sessionStorage.removeItem("pageCache-dirty")
197  }
198
199  var getDirties = function() {
200    var raw = sessionStorage.getItem("pageCache-dirty")
201    if (raw) {
202      var json = JSON.parse(raw)
203      return jQuery.map(json, function(value, key){
204        return key
205      })
206    } else {
207      return null
208    }
209  }
210
211  var markDirty = function(item) {
212    SessionStorageHash.set("pageCache-dirty", item, true)
213  }
214
215  var trimStorage = function(){
216    var storageHash = sessionStorage.getItem("pageCache");
217    if(storageHash){
218      storageHash = JSON.parse(storageHash);
219
220      var tuples = [];
221
222      for (var key in storageHash) {
223        tuples.push([key, storageHash[key]])
224      }
225      // if storage is bigger than size, sort them, and remove oldest
226      if(tuples.length >= 10){
227        tuples.sort(function(a, b) {
228            a = a[1].cachedAt;
229            b = b[1].cachedAt;
230            return b < a ? -1 : (b > a ? 1 : 0);
231        });
232
233        for (var i = 0; i < (tuples.length + 1 - 10); i++) {
234          var key = tuples[i][0];
235          delete storageHash[key];
236        }
237
238        sessionStorage.setItem(namespace, JSON.stringify(storageHash));
239      }
240    }
241  }
242
243  var willUseCacheOnThisPage = function(){
244    if (!supported()){
245      return false;
246    }
247
248    var cachedPage = getItem(document.location.href)
249
250    // Check if there is a cache and if its less than 15 minutes old
251    if(cachedPage && cachedPage.cachedAt > (new Date().getTime()-900000)){
252      return true; 
253    }
254    else{
255      return false;
256    }
257  }
258
259  jQuery(document).ready(function(){
260    disableAutofocusIfReplacingCachedPage()
261  });
262
263  jQuery(window).load(function(){
264    loadFromCache()
265  });
266
267  return {
268    enable: enable,
269    disable: disable,
270    remove: removeItem,
271    loadFromCache: loadFromCache,
272    cachePage: cachePage,
273    markDirty: markDirty, 
274    willUseCacheOnThisPage: willUseCacheOnThisPage
275  }
276});