feat: add option to disable infinite scroll (#1253)

* feat: add option to disable infinite scroll

fixes #391 and fixes #270. Also makes me less nervous about #1251 because now keyboard users can disable infinite load and easily access the "reload" button in the snackbar footer.

* fix test

src/routes/_actions/timeline.js

@@ -114,7 +114,7 @@ export async function setupTimeline () {
   stop('setupTimeline')
 }
 
-export async function fetchTimelineItemsOnScrollToBottom (instanceName, timelineName) {
+export async function fetchMoreItemsAtBottomOfTimeline (instanceName, timelineName) {
   console.log('setting runningUpdate: true')
   store.setForTimeline(instanceName, timelineName, { runningUpdate: true })
   await fetchTimelineItemsAndPossiblyFallBack()

src/routes/_components/timeline/LoadingFooter.html

@@ -1,29 +1,97 @@
 <div class="loading-footer {shown ? '' : 'hidden'}">
+  <div class="loading-wrapper {showLoading ? 'shown' : ''}"
+       aria-hidden={!showLoading}
+       role="alert"
+  >
     <LoadingSpinner size={48} />
     <span class="loading-footer-info">
       Loading more...
     </span>
+  </div>
+  <div class="button-wrapper {showLoadButton ? 'shown' : ''}"
+       aria-hidden={!showLoadButton}
+  >
+    <button type="button"
+            class="primary"
+            on:click="onClickLoadMore(event)">
+      Load more
+    </button>
+  </div>
 </div>
 <style>
   .loading-footer {
-    padding: 20px 0 10px;
+    padding: 20px 0;
     display: flex;
     align-items: center;
     justify-content: center;
+    position: relative;
+  }
+  .loading-wrapper {
+    flex: 1;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    opacity: 0;
+    pointer-events: none;
+    transition: opacity 0.2s linear;
+  }
+  .loading-wrapper.shown {
+    opacity: 1;
+    pointer-events: auto;
   }
   .loading-footer-info {
     margin-left: 20px;
     font-size: 1.3em;
   }
+  .button-wrapper {
+    position: absolute;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    top: 0;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    opacity: 0;
+    pointer-events: none;
+    transition: none;
+  }
+  .button-wrapper.shown {
+    opacity: 1;
+    pointer-events: auto;
+    transition: opacity 0.2s linear 0.2s;
+  }
 </style>
 <script>
   import LoadingSpinner from '../LoadingSpinner.html'
   import { store } from '../../_store/store'
+  import { fetchMoreItemsAtBottomOfTimeline } from '../../_actions/timeline'
 
   export default {
     store: () => store,
     computed: {
-      shown: ({ $timelineInitialized, $runningUpdate }) => ($timelineInitialized && $runningUpdate)
+      shown: ({ $timelineInitialized, $runningUpdate, $disableInfiniteScroll }) => (
+        $timelineInitialized && ($disableInfiniteScroll || $runningUpdate)
+      ),
+      showLoading: ({ $runningUpdate }) => $runningUpdate,
+      showLoadButton: ({ $runningUpdate, $disableInfiniteScroll }) => !$runningUpdate && $disableInfiniteScroll
+    },
+    methods: {
+      onClickLoadMore (e) {
+        e.preventDefault()
+        e.stopPropagation()
+        let { currentInstance, currentTimeline } = this.store.get()
+        /* no await */ fetchMoreItemsAtBottomOfTimeline(currentInstance, currentTimeline)
+        // focus the last item in the timeline; it makes the most sense to me since the button disappears
+        try {
+          // TODO: should probably expose this as an API on the virtual list instead of reaching into the DOM
+          let virtualListItems = document.querySelector('.virtual-list').children
+          let lastItem = virtualListItems[virtualListItems.length - 2] // -2 because the footer is last
+          lastItem.querySelector('article').focus()
+        } catch (e) {
+          console.error(e)
+        }
+      }
     },
     components: {
       LoadingSpinner

src/routes/_components/timeline/Timeline.html

@@ -45,7 +45,7 @@
   } from '../../_utils/asyncModules'
   import { timelines } from '../../_static/timelines'
   import {
-    fetchTimelineItemsOnScrollToBottom,
+    fetchMoreItemsAtBottomOfTimeline,
     setupTimeline,
     showMoreItemsForTimeline,
     showMoreItemsForThread,
@@ -165,18 +165,16 @@
       },
       onScrollToBottom () {
         let { timelineType } = this.get()
-        let { timelineInitialized, runningUpdate } = this.store.get()
+        let { timelineInitialized, runningUpdate, disableInfiniteScroll } = this.store.get()
         if (!timelineInitialized ||
             runningUpdate ||
+            disableInfiniteScroll ||
             timelineType === 'status') { // for status contexts, we've already fetched the whole thread
           return
         }
         let { currentInstance } = this.store.get()
         let { timeline } = this.get()
-        fetchTimelineItemsOnScrollToBottom(
-          currentInstance,
-          timeline
-        )
+        /* no await */ fetchMoreItemsAtBottomOfTimeline(currentInstance, timeline)
       },
       onScrollToTop () {
         let { shouldShowHeader } = this.store.get()
@@ -188,7 +186,7 @@
         }
       },
       setupStreaming () {
-        let { currentInstance } = this.store.get()
+        let { currentInstance, disableInfiniteScroll } = this.store.get()
         let { timeline, timelineType } = this.get()
         let handleItemIdsToAdd = () => {
           let { itemIdsToAdd } = this.get()
@@ -204,13 +202,17 @@
           if (timelineType === 'status') {
             // this is a thread, just insert the statuses already
             showMoreItemsForThread(currentInstance, timeline)
-          } else if (scrollTop === 0 && !shouldShowHeader && !showHeader) {
+          } else if (!disableInfiniteScroll && scrollTop === 0 && !shouldShowHeader && !showHeader) {
             // if the user is scrolled to the top and we're not showing the header, then
             // just insert the statuses. this is "chat room mode"
             showMoreItemsForTimeline(currentInstance, timeline)
           } else {
             // user hasn't scrolled to the top, show a header instead
             this.store.setForTimeline(currentInstance, timeline, { shouldShowHeader: true })
+            // unless the user has disabled infinite scroll entirely
+            if (disableInfiniteScroll) {
+              this.store.setForTimeline(currentInstance, timeline, { showHeader: true })
+            }
           }
           stop('handleItemIdsToAdd')
         }

src/routes/_pages/settings/general.html

@@ -32,6 +32,19 @@
              bind:checked="$disableCustomScrollbars" on:change="onChange(event)">
       <label for="choice-disable-custom-scrollbars">Disable custom scrollbars</label>
     </div>
+    <div class="setting-group">
+      <input type="checkbox" id="choice-disable-infinite-scroll"
+             bind:checked="$disableInfiniteScroll" on:change="onChange(event)">
+      <label for="choice-disable-infinite-scroll">Disable
+        <Tooltip
+          text="infinite scroll"
+          tooltipText={
+            "When infinite scroll is disabled, new toots will not automatically appear at the bottom " +
+            "or top of the timeline. Instead, buttons will allow you to load more content on demand."
+          }
+        />
+      </label>
+    </div>
     <div class="setting-group">
       <input type="checkbox" id="choice-hide-cards"
              bind:checked="$hideCards" on:change="onChange(event)">
@@ -89,11 +102,13 @@
   import SettingsLayout from '../../_components/settings/SettingsLayout.html'
   import ThemeSettings from '../../_components/settings/instance/ThemeSettings.html'
   import { store } from '../../_store/store'
+  import Tooltip from '../../_components/Tooltip.html'
 
   export default {
     components: {
       SettingsLayout,
-      ThemeSettings
+      ThemeSettings,
+      Tooltip
     },
     methods: {
       onChange (event) {

src/routes/_store/store.js

@@ -13,6 +13,7 @@ const persistedState = {
   // we disable scrollbars by default on iOS
   disableCustomScrollbars: process.browser && /iP(?:hone|ad|od)/.test(navigator.userAgent),
   disableHotkeys: false,
+  disableInfiniteScroll: false,
   disableLongAriaLabels: false,
   disableTapOnStatus: false,
   hideCards: false,

tests/spec/036-disable-infinite-load.js

@@ -0,0 +1,39 @@
+import {
+  settingsNavButton,
+  homeNavButton,
+  disableInfiniteScroll,
+  scrollToStatus,
+  loadMoreButton, getFirstVisibleStatus, scrollFromStatusToStatus, sleep, getActiveElementAriaPosInSet
+} from '../utils'
+import { loginAsFoobar } from '../roles'
+import { Selector as $ } from 'testcafe'
+
+fixture`036-disable-infinite-load.js`
+  .page`http://localhost:4002`
+
+test('Can disable loading items at bottom of timeline', async t => {
+  await loginAsFoobar(t)
+  await t.click(settingsNavButton)
+    .click($('a').withText('General'))
+    .click(disableInfiniteScroll)
+    .expect(disableInfiniteScroll.checked).ok()
+    .click(homeNavButton)
+    .expect(getFirstVisibleStatus().getAttribute('aria-setsize')).eql('20')
+  await scrollToStatus(t, 20)
+  await t
+    .click(loadMoreButton)
+    .expect(getActiveElementAriaPosInSet()).eql('20')
+    .expect(getFirstVisibleStatus().getAttribute('aria-setsize')).eql('40')
+  await scrollFromStatusToStatus(t, 20, 40)
+  await t
+    .click(loadMoreButton)
+    .expect(getActiveElementAriaPosInSet()).eql('40')
+    .expect(getFirstVisibleStatus().getAttribute('aria-setsize')).eql('47')
+  await scrollFromStatusToStatus(t, 40, 47)
+  await t
+    .click(loadMoreButton)
+  await sleep(1000)
+  await t
+    .expect(loadMoreButton.exists).ok()
+    .expect(getFirstVisibleStatus().getAttribute('aria-setsize')).eql('47')
+})

tests/spec/128-disable-infinite-load.js

@@ -0,0 +1,32 @@
+import {
+  settingsNavButton,
+  homeNavButton,
+  disableInfiniteScroll,
+  getFirstVisibleStatus,
+  getUrl,
+  showMoreButton, getNthStatusContent
+} from '../utils'
+import { loginAsFoobar } from '../roles'
+import { Selector as $ } from 'testcafe'
+import { postAs } from '../serverActions'
+
+fixture`128-disable-infinite-load.js`
+  .page`http://localhost:4002`
+
+test('Can disable loading items at top of timeline', async t => {
+  await loginAsFoobar(t)
+  await t.click(settingsNavButton)
+    .click($('a').withText('General'))
+    .click(disableInfiniteScroll)
+    .expect(disableInfiniteScroll.checked).ok()
+    .click(homeNavButton)
+    .expect(getUrl()).eql('http://localhost:4002/')
+    .expect(getFirstVisibleStatus().exists).ok()
+  await postAs('admin', 'hey hey hey this is new')
+  await t
+    .expect(showMoreButton.innerText).contains('Show 1 more', {
+      timeout: 20000
+    })
+    .click(showMoreButton)
+    .expect(getNthStatusContent(1).innerText).contains('hey hey hey this is new')
+})

tests/utils.js

@@ -48,11 +48,14 @@ export const generalSettingsButton = $('a[href="/settings/general"]')
 export const markMediaSensitiveInput = $('#choice-mark-media-sensitive')
 export const neverMarkMediaSensitiveInput = $('#choice-never-mark-media-sensitive')
 export const removeEmojiFromDisplayNamesInput = $('#choice-omit-emoji-in-display-names')
+export const disableInfiniteScroll = $('#choice-disable-infinite-scroll')
 export const dialogOptionsOption = $(`.modal-dialog button`)
 export const emojiSearchInput = $('.emoji-mart-search input')
 export const confirmationDialogOKButton = $('.confirmation-dialog-form-flex button:nth-child(1)')
 export const confirmationDialogCancelButton = $('.confirmation-dialog-form-flex button:nth-child(2)')
 
+export const loadMoreButton = $('.loading-footer button')
+
 export const composeModalInput = $('.modal-dialog .compose-box-input')
 export const composeModalComposeButton = $('.modal-dialog .compose-box-button')
 export const composeModalContentWarningInput = $('.modal-dialog .content-warning-input')
@@ -119,6 +122,10 @@ export const getActiveElementRectTop = exec(() => (
   (document.activeElement && document.activeElement.getBoundingClientRect().top) || -1
 ))
 
+export const getActiveElementAriaPosInSet = exec(() => (
+  (document.activeElement && document.activeElement.getAttribute('aria-posinset')) || ''
+))
+
 export const getActiveElementInsideNthStatus = exec(() => {
   let element = document.activeElement
   while (element) {
@@ -428,16 +435,20 @@ export async function validateTimeline (t, timeline) {
 }
 
 export async function scrollToStatus (t, n) {
+  return scrollFromStatusToStatus(t, 1, n)
+}
+
+export async function scrollFromStatusToStatus (t, start, end) {
   let timeout = 20000
-  for (let i = 1; i < n; i++) {
+  for (let i = start; i < end; i++) {
     await t.expect(getNthStatus(i).exists).ok({ timeout })
       .hover(getNthStatus(i))
-      .expect($('.loading-footer').exist).notOk({ timeout })
       .expect($(`${getNthStatusSelector(i)} .status-toolbar`).exists).ok({ timeout })
       .hover($(`${getNthStatusSelector(i)} .status-toolbar`))
-      .expect($('.loading-footer').exist).notOk({ timeout })
   }
-  await t.hover(getNthStatus(n))
+  await t
+    .expect(getNthStatus(end).exists).ok({ timeout })
+    .hover(getNthStatus(end))
 }
 
 export async function clickToNotificationsAndBackHome (t) {