From 4b79a5af0f89c792c79c379c681dc85414da7c76 Mon Sep 17 00:00:00 2001
From: nicwands <wands.nic@gmail.com>
Date: Fri, 19 Jun 2026 15:14:20 -0400
Subject: [PATCH] move to virtual scrolling

---
 src/App.vue                                |   2 +-
 src/components/InfiniteScrollContainer.vue |  32 +++---
 src/components/Layout.vue                  |   4 +-
 src/components/MosaicScroll.vue            |  19 +++-
 src/components/MosaicViewport.vue          |   1 +
 src/components/site/Header.vue             |   3 +-
 src/components/strapi/Content.vue          |   5 +
 src/composables/useInfiniteScroll.js       | 124 ++++++++++-----------
 src/plugins/gsap.js                        |  15 +++
 9 files changed, 120 insertions(+), 85 deletions(-)
 create mode 100644 src/plugins/gsap.js

diff --git a/src/App.vue b/src/App.vue
index 18ffa7c..9f9bf57 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -1,5 +1,5 @@
 <template>
-    <lenis root :options="{ duration: 1 }">
+    <lenis root :options="{ duration: 1, infinite: true, syncTouch: true }">
         <div :class="classes" :style="styles" id="container">
             <suspense>
                 <layout />
diff --git a/src/components/InfiniteScrollContainer.vue b/src/components/InfiniteScrollContainer.vue
index fbac68a..b84821a 100644
--- a/src/components/InfiniteScrollContainer.vue
+++ b/src/components/InfiniteScrollContainer.vue
@@ -1,13 +1,12 @@
 <template>
     <div class="infinite-scroll-container">
-        <div class="wrapper" :style="{ height: totalHeight + 'px' }">
-            <!-- Render visible viewports -->
+        <transition-group name="fade" tag="div" class="viewport-stage">
             <div
                 v-for="viewport in visibleViewports"
                 class="viewport"
                 :style="{
-                    top: viewport.offsetY + 'px',
                     height: viewport.height + 'px',
+                    transform: `translateY(${viewport.offsetY - scrollY}px)`,
                 }"
                 :key="viewport.index"
             >
@@ -25,11 +24,12 @@
                     </div>
                 </slot>
             </div>
-        </div>
+        </transition-group>
     </div>
 </template>
 
 <script setup>
+import { watch } from 'vue'
 import { useInfiniteScroll } from '@/composables/useInfiniteScroll'
 
 const props = defineProps({
@@ -74,11 +74,11 @@ const emit = defineEmits(['viewport-change', 'content-loaded'])
 const {
     currentViewportIndex,
     visibleViewports,
-    totalHeight,
     scrollY,
-    scrollToViewport,
     reset,
     retryViewport,
+    start,
+    stop,
     hasError,
     errors,
     _state,
@@ -93,43 +93,45 @@ const {
     initialIndex: props.initialIndex,
 })
 
-// Watch for viewport changes and emit event
-import { watch } from 'vue'
 watch(currentViewportIndex, (newIndex, oldIndex) => {
     emit('viewport-change', { newIndex, oldIndex })
 })
 
-// Expose methods to parent component
 defineExpose({
-    scrollToViewport,
     reset,
     retryViewport,
+    start,
+    stop,
     currentViewportIndex,
     visibleViewports,
-    totalHeight,
     scrollY,
     hasError,
     errors,
-    // Debug access
     _state,
 })
 </script>
 
 <style lang="scss">
 .infinite-scroll-container {
-    position: relative;
+    position: fixed;
+    inset: 0;
     width: 100%;
+    height: 100vh;
+    overflow: hidden;
 
-    .wrapper {
+    .viewport-stage {
         position: relative;
         width: 100%;
-        min-height: 100vh;
+        height: 100%;
     }
 
     .viewport {
         box-sizing: border-box;
         position: absolute;
+        top: 0;
+        left: 0;
         width: 100%;
+        will-change: transform;
     }
 }
 </style>
diff --git a/src/components/Layout.vue b/src/components/Layout.vue
index 5047f2d..0f844b9 100644
--- a/src/components/Layout.vue
+++ b/src/components/Layout.vue
@@ -2,7 +2,7 @@
     <div v-if="global" class="layout">
         <site-header :copy="headerCopy" :dl="headerDl" />
 
-        <client-only>
+         <client-only>
             <mosaic-scroll :items="mosaicItems" />
         </client-only>
 
@@ -17,7 +17,7 @@
 </template async>
 
 <script setup>
-import { computed } from 'vue';
+import { computed} from 'vue';
 import { useSeoMeta } from '@unhead/vue'
 import { useStrapiGlobal } from '@/composables/useStrapi'
 import { useRoute } from 'vue-router';
diff --git a/src/components/MosaicScroll.vue b/src/components/MosaicScroll.vue
index 0009013..8924cda 100644
--- a/src/components/MosaicScroll.vue
+++ b/src/components/MosaicScroll.vue
@@ -4,6 +4,7 @@
             :bufferSize="2"
             :initialIndex="0"
             :generateContent="generateMosaicContent"
+            ref="scrollContainer"
         >
             <template #viewport="{ viewport, content }">
                 <mosaic-viewport :viewport="viewport" :content="content" />
@@ -13,9 +14,10 @@
 </template>
 
 <script setup>
-import { ref } from 'vue'
+import { ref, watch } from 'vue'
 import _shuffle from 'lodash/shuffle'
 import { useMosaicLayout } from '@/composables/useMosaicLayout'
+import { useRoute } from 'vue-router'
 
 const props = defineProps({
     items: Array,
@@ -23,8 +25,10 @@ const props = defineProps({
 
 const itemIndex = ref(0)
 const shuffledItems = ref(_shuffle(props.items))
+const scrollContainer = ref(null)
 
 const { generateLayout, populateCells } = useMosaicLayout()
+const route = useRoute()
 
 const generateCellContent = () => {
     if (itemIndex.value >= shuffledItems.value.length - 1) {
@@ -61,6 +65,19 @@ const generateMosaicContent = async (index) => {
         cells: populatedCells,
     }
 }
+
+// Start/stop scroll when page is open
+watch(
+    () => route.name,
+    () => {
+        if (route.name === 'mosaic-item') {
+            scrollContainer.value?.stop?.()
+        } else {
+            scrollContainer.value?.start?.()
+        }
+    },
+    { immediate: true },
+)
 </script>
 
 <style lang="scss">
diff --git a/src/components/MosaicViewport.vue b/src/components/MosaicViewport.vue
index 76a38f4..9b6fe78 100644
--- a/src/components/MosaicViewport.vue
+++ b/src/components/MosaicViewport.vue
@@ -61,6 +61,7 @@ const props = defineProps({
             display: flex;
             justify-content: center;
             align-items: center;
+            background: var(--theme-bg);
 
             &.layout-portrait {
                 .strapi-media {
diff --git a/src/components/site/Header.vue b/src/components/site/Header.vue
index 8aed55e..d4a9f9a 100644
--- a/src/components/site/Header.vue
+++ b/src/components/site/Header.vue
@@ -50,7 +50,8 @@ const props = defineProps({
             strong {
                 @include h6;
             }
-            p {
+            p,
+            a {
                 margin: desktop-vw(6px) 0;
                 @include p-small;
             }
diff --git a/src/components/strapi/Content.vue b/src/components/strapi/Content.vue
index aa3629b..84cc776 100644
--- a/src/components/strapi/Content.vue
+++ b/src/components/strapi/Content.vue
@@ -30,6 +30,11 @@ const props = defineProps({
         background: var(--grey);
         border-radius: desktop-vw(2px);
         padding: desktop-vw(20px);
+        overflow-x: auto;
+    }
+
+    a {
+        text-decoration: underline;
     }
 }
 </style>
diff --git a/src/composables/useInfiniteScroll.js b/src/composables/useInfiniteScroll.js
index 981502b..929d546 100644
--- a/src/composables/useInfiniteScroll.js
+++ b/src/composables/useInfiniteScroll.js
@@ -1,13 +1,16 @@
-import { ref, reactive, computed, nextTick } from 'vue'
+import gsap from 'gsap'
 import { useWindowSize } from '@vueuse/core'
 import useLenis from '@/composables/useLenis'
+import { ref, reactive, computed, nextTick, onBeforeUnmount, watch } from 'vue'
 
 // Window size for viewport calculations
 const { height: wHeight } = useWindowSize()
 
 /**
- * Bidirectional infinite scroll composable
- * Manages virtual viewports with on-demand content generation
+ * Bidirectional infinite virtual scroll composable
+ * Manages virtual viewports with on-demand content generation.
+ * The page stays at 100vh — scroll position is tracked via Lenis
+ * virtual-scroll events and viewports are positioned with CSS transforms.
  *
  * @param {Object} options Configuration options
  * @param {Function} options.generateContent Function to generate content for a viewport
@@ -32,8 +35,10 @@ export const useInfiniteScroll = (options = {}) => {
 
     // Core state
     const state = reactive({
-        // Current scroll position
-        scrollY: 0,
+        // Accumulated virtual scroll position (not the real DOM scroll)
+        scrollY: initialIndex * (viewportHeight || 0),
+        // Active state to stop/start scroll
+        active: true,
         // Index of the currently visible viewport
         currentViewportIndex: initialIndex,
         // Map of loaded viewports { index: { content, element, height, offsetY } }
@@ -41,8 +46,6 @@ export const useInfiniteScroll = (options = {}) => {
         // Loading states
         isLoadingUp: false,
         isLoadingDown: false,
-        // Total virtual height (for scrollbar)
-        totalHeight: 0,
         // Error handling
         errors: new Map(),
         hasError: false,
@@ -51,7 +54,9 @@ export const useInfiniteScroll = (options = {}) => {
 
     // Initialize with starting viewport
     const initializeViewports = async () => {
-        // Create initial viewport
+        // Seed scrollY once vpHeight is available
+        state.scrollY = initialIndex * vpHeight.value
+
         const initialViewport = {
             index: initialIndex,
             content: await generateContent(initialIndex),
@@ -61,15 +66,12 @@ export const useInfiniteScroll = (options = {}) => {
 
         state.viewports.set(initialIndex, initialViewport)
 
-        // Load buffer viewports above and below
         await loadViewportsInRange(
             initialIndex - bufferSize,
             initialIndex + bufferSize,
         )
 
-        // Update positions and total height
         updateViewportPositions()
-        updateTotalHeight()
     }
 
     // Load viewports in a range
@@ -92,7 +94,6 @@ export const useInfiniteScroll = (options = {}) => {
         const currentRetryCount = state.retryCount.get(index) || 0
 
         try {
-            // Set loading state based on direction
             if (index < state.currentViewportIndex) {
                 state.isLoadingUp = true
             } else if (index > state.currentViewportIndex) {
@@ -109,7 +110,6 @@ export const useInfiniteScroll = (options = {}) => {
 
             state.viewports.set(index, viewport)
 
-            // Clear any previous errors for this viewport
             state.errors.delete(index)
             state.retryCount.delete(index)
             state.hasError = state.errors.size > 0
@@ -118,7 +118,6 @@ export const useInfiniteScroll = (options = {}) => {
         } catch (error) {
             console.error(`Failed to load viewport ${index}:`, error)
 
-            // Store error
             state.errors.set(index, {
                 message: error.message || 'Failed to load content',
                 timestamp: Date.now(),
@@ -126,54 +125,26 @@ export const useInfiniteScroll = (options = {}) => {
             })
             state.hasError = true
 
-            // Retry logic
             if (currentRetryCount < maxRetries && !isRetry) {
                 state.retryCount.set(index, currentRetryCount + 1)
-                console.log(
-                    `Retrying viewport ${index} (attempt ${currentRetryCount + 1}/${maxRetries})`,
-                )
-
-                // Exponential backoff
                 const delay = Math.pow(2, currentRetryCount) * 1000
-                setTimeout(() => {
-                    loadViewport(index, true)
-                }, delay)
+                setTimeout(() => loadViewport(index, true), delay)
             }
 
             return null
         } finally {
-            // Clear loading states
             state.isLoadingUp = false
             state.isLoadingDown = false
         }
     }
 
-    // Update viewport positions based on their order
+    // Update viewport positions based on their index
     const updateViewportPositions = () => {
-        // Each viewport is positioned at index * viewport height
         for (const [index, viewport] of state.viewports) {
             viewport.offsetY = index * vpHeight.value
         }
     }
 
-    // Update total virtual height for scrollbar
-    const updateTotalHeight = () => {
-        if (state.viewports.size === 0) {
-            state.totalHeight = wHeight.value * bufferSize // Minimum height
-            return
-        }
-
-        const indexes = Array.from(state.viewports.keys())
-        // const minIndex = Math.min(...indexes)
-        const maxIndex = Math.max(...indexes)
-
-        // Calculate total height needed to accommodate all viewports
-        // Add extra buffer above and below for infinite scroll
-        const bufferViewports = 10
-        const totalRange = maxIndex + bufferViewports
-        state.totalHeight = totalRange * vpHeight.value
-    }
-
     // Remove viewports outside buffer range
     const cleanupViewports = () => {
         const currentIndex = state.currentViewportIndex
@@ -185,37 +156,56 @@ export const useInfiniteScroll = (options = {}) => {
                 state.viewports.delete(index)
             }
         }
-
-        updateTotalHeight()
     }
 
-    // Calculate which viewport should be visible based on scroll position
+    // Calculate which viewport should be visible based on virtual scroll position
     const calculateVisibleViewport = (scrollY) => {
         return Math.floor(scrollY / vpHeight.value)
     }
 
-    // Handle scroll events
-    const handleScroll = async (scrollData) => {
-        state.scrollY = scrollData.scroll
+    // Handle virtual-scroll delta events from Lenis
+    const onVirtualScroll = async ({ deltaY }) => {
+        if (!state.active) return
+
+        deltaY *= 3
+
+        gsap.to(state, {
+            scrollY: state.scrollY + deltaY,
+            duration: 1,
+            ease: 'expo.out',
+        })
 
         const newViewportIndex = calculateVisibleViewport(state.scrollY)
 
         if (newViewportIndex !== state.currentViewportIndex) {
             state.currentViewportIndex = newViewportIndex
 
-            // Load new viewports in range
             const rangeStart = newViewportIndex - bufferSize
             const rangeEnd = newViewportIndex + bufferSize
 
             await loadViewportsInRange(rangeStart, rangeEnd)
-
-            // Cleanup old viewports
             cleanupViewports()
         }
     }
 
-    // Setup scroll listener with Lenis
-    const lenis = useLenis(handleScroll)
+    // Setup Lenis — we use virtual-scroll instead of scroll so the DOM
+    // height can stay at 100vh with overflow: hidden.
+    const lenis = useLenis()
+
+    // Attach the virtual-scroll listener once Lenis is ready
+    watch(
+        lenis,
+        (instance) => {
+            if (instance) {
+                instance.on('virtual-scroll', onVirtualScroll)
+            }
+        },
+        { immediate: true },
+    )
+
+    onBeforeUnmount(() => {
+        lenis.value?.off('virtual-scroll', onVirtualScroll)
+    })
 
     // Get viewports to render (current + buffer)
     const visibleViewports = computed(() => {
@@ -234,14 +224,6 @@ export const useInfiniteScroll = (options = {}) => {
         return viewports.sort((a, b) => a.index - b.index)
     })
 
-    // Scroll to a specific viewport
-    const scrollToViewport = (index) => {
-        if (lenis.value) {
-            const targetY = index * vpHeight.value
-            lenis.value.scrollTo(targetY, { immediate: false })
-        }
-    }
-
     // Retry failed viewport
     const retryViewport = async (index) => {
         state.errors.delete(index)
@@ -257,11 +239,22 @@ export const useInfiniteScroll = (options = {}) => {
         state.retryCount.clear()
         state.hasError = false
         state.currentViewportIndex = initialIndex
+        state.scrollY = initialIndex * vpHeight.value
         state.isLoadingUp = false
         state.isLoadingDown = false
         await initializeViewports()
     }
 
+    // Start/stop scrolling
+    const stop = () => {
+        state.active = false
+
+        gsap.killTweensOf(state)
+    }
+    const start = () => {
+        state.active = true
+    }
+
     // Initialize on creation
     nextTick(() => {
         initializeViewports()
@@ -274,13 +267,14 @@ export const useInfiniteScroll = (options = {}) => {
         visibleViewports,
         isLoadingUp: computed(() => state.isLoadingUp),
         isLoadingDown: computed(() => state.isLoadingDown),
-        totalHeight: computed(() => state.totalHeight),
         scrollY: computed(() => state.scrollY),
+        vpHeight,
 
         // Methods
-        scrollToViewport,
         reset,
         retryViewport,
+        stop,
+        start,
 
         // Error state
         hasError: computed(() => state.hasError),
diff --git a/src/plugins/gsap.js b/src/plugins/gsap.js
new file mode 100644
index 0000000..cb72813
--- /dev/null
+++ b/src/plugins/gsap.js
@@ -0,0 +1,15 @@
+import gsap from 'gsap'
+import Tempus from 'tempus'
+
+export default {
+    install: () => {
+        gsap.defaults({ ease: 'none' })
+
+        // merge rafs
+        gsap.ticker.lagSmoothing(0)
+        gsap.ticker.remove(gsap.updateRoot)
+        Tempus?.add((time) => {
+            gsap.updateRoot(time / 1000)
+        }, 0)
+    },
+}