https://www.backsplash.com/wp-content/themes/flatsome/inc/extensio…/flatsome-instant-page.js?ver=dbfc65337a32

1// modified to work without type="module"
2
3;(function () {
4  /*! instant.page v1.2.2 - (C) 2019 Alexandre Dieulot - https://instant.page/license */
5
6  var urlToPreload
7  var mouseoverTimer
8  var lastTouchTimestamp
9
10  var prefetcher = document.createElement('link')
11  var isSupported = prefetcher.relList && prefetcher.relList.supports && prefetcher.relList.supports('prefetch')
12  var isDataSaverEnabled = navigator.connection && navigator.connection.saveData
13  var allowQueryString = 'instantAllowQueryString' in document.body.dataset
14  var allowExternalLinks = 'instantAllowExternalLinks' in document.body.dataset
15
16  if (isSupported && !isDataSaverEnabled) {
17    prefetcher.rel = 'prefetch'
18    document.head.appendChild(prefetcher)
19
20    var eventListenersOptions = {
21      capture: true,
22      passive: true
23    }
24    document.addEventListener('touchstart', touchstartListener, eventListenersOptions)
25    document.addEventListener('mouseover', mouseoverListener, eventListenersOptions)
26  }
27
28  function touchstartListener (event) {
29    /* Chrome on Android calls mouseover before touchcancel so `lastTouchTimestamp`
30     * must be assigned on touchstart to be measured on mouseover. */
31    lastTouchTimestamp = performance.now()
32
33    var linkElement = event.target.closest('a')
34
35    if (!isPreloadable(linkElement)) {
36      return
37    }
38
39    linkElement.addEventListener('touchcancel', touchendAndTouchcancelListener, { passive: true })
40    linkElement.addEventListener('touchend', touchendAndTouchcancelListener, { passive: true })
41
42    urlToPreload = linkElement.href
43    preload(linkElement.href)
44  }
45
46  function touchendAndTouchcancelListener () {
47    urlToPreload = undefined
48    stopPreloading()
49  }
50
51  function mouseoverListener (event) {
52    if (performance.now() - lastTouchTimestamp < 1100) {
53      return
54    }
55
56    var linkElement = event.target.closest('a')
57
58    if (!isPreloadable(linkElement)) {
59      return
60    }
61
62    linkElement.addEventListener('mouseout', mouseoutListener, { passive: true })
63
64    urlToPreload = linkElement.href
65
66    mouseoverTimer = setTimeout(function () {
67      preload(linkElement.href)
68      mouseoverTimer = undefined
69    }, 65)
70  }
71
72  function mouseoutListener (event) {
73    if (event.relatedTarget && event.target.closest('a') === event.relatedTarget.closest('a')) {
74      return
75    }
76
77    if (mouseoverTimer) {
78      clearTimeout(mouseoverTimer)
79      mouseoverTimer = undefined
80    } else {
81      urlToPreload = undefined
82      stopPreloading()
83    }
84  }
85
86  function isPreloadable (linkElement) {
87    if (!linkElement || !linkElement.href) {
88      return
89    }
90
91    if (urlToPreload === linkElement.href) {
92      return
93    }
94
95    var preloadLocation = new URL(linkElement.href)
96
97    if (!allowExternalLinks && preloadLocation.origin !== location.origin && !('instant' in linkElement.dataset)) {
98      return
99    }
100
101    if (!['http:', 'https:'].includes(preloadLocation.protocol)) {
102      return
103    }
104
105    if (preloadLocation.protocol === 'http:' && location.protocol === 'https:') {
106      return
107    }
108
109    if (!allowQueryString && preloadLocation.search && !('instant' in linkElement.dataset)) {
110      return
111    }
112
113    if (preloadLocation.hash && preloadLocation.pathname + preloadLocation.search === location.pathname + location.search) {
114      return
115    }
116
117    if ('noInstant' in linkElement.dataset) {
118      return
119    }
120
121    return true
122  }
123
124  function preload (url) {
125    prefetcher.href = url
126  }
127
128  function stopPreloading () {
129    prefetcher.removeAttribute('href')
130  }
131})()