feat: support horizontal scrolling (#141)

README.md

@@ -13,7 +13,8 @@ items (e.g. 1000+ items) as a grid in a performant way.
 - Just use CSS grid to style your grid. Minimum styling opinions form the
   library.
 - Support using a paginated API to load the items in the background.
-- Support rendering placeholders for unloaded items
+- Support rendering placeholders for unloaded items.
+- Support both vertical and horizontal scroll.
 - Loaded items are cached for better performance.
 
 ## Code Examples
@@ -36,7 +37,7 @@ npm install vue-virtual-scroll-grid
 | `pageProviderDebounceTime` | Debounce window in milliseconds on the calls to `pageProvider`                    | `number`                                                       | Optional, an integer greater than or equal to 0      |
 | `pageSize`                 | The number of items in a page from the item provider (e.g. a backend API)         | `number`                                                       | Required, an integer greater than or equal to 1      |
 | `scrollTo`                 | Scroll to a specific item by index                                                | `number`                                                       | Optional, an integer from 0 to the `length` prop - 1 |
-| `scrollBehavior`           | The behavior of `scrollTo`. Default value is `smooth`                             | `smooth` | `auto`                                              | Optional, a string to be `smooth` or `auto`         |
+| `scrollBehavior`           | The behavior of `scrollTo`. Default value is `smooth`                             | `smooth` | `auto`                                         | Optional, a string to be `smooth` or `auto`         |
 
 Example:
 
@@ -113,6 +114,11 @@ Example:
 </template>
 ```
 
+## Scroll Mode
+
+The library uses `grid-auto-flow` CSS property to infer scroll mode. Set it to
+`column` value if you want to enable horizontal scroll.
+
 ## Caveats
 
 The library does not require items have foreknown width and height, but do

src/Grid.vue

@@ -1,12 +1,5 @@
 <template>
-  <div
-    v-show="length > 0"
-    ref="rootRef"
-    :style="{
-      height: `${contentHeight}px`,
-      placeContent: 'start',
-    }"
-  >
+  <div v-show="length > 0" ref="rootRef" :style="rootStyles">
     <div
       :style="{
         opacity: 0,
@@ -40,7 +33,14 @@
 </template>
 
 <script lang="ts">
-import { defineComponent, onUpdated, PropType, ref } from "vue";
+import {
+  defineComponent,
+  onUpdated,
+  PropType,
+  ref,
+  computed,
+  StyleValue,
+} from "vue";
 import {
   fromProp,
   fromResizeObserver,
@@ -100,7 +100,7 @@ export default defineComponent({
     // data to render
     const {
       buffer$, // the items in the current scanning window
-      contentHeight$, // the height of the whole list
+      contentSize$, // the size of the whole list
       scrollAction$, // the value sent to window.scrollTo()
     } = pipeline({
       // streams of prop
@@ -119,17 +119,28 @@ export default defineComponent({
 
     onUpdated(
       once(() => {
-        scrollAction$.subscribe(([el, top]: ScrollAction) => {
-          el.scrollTo({ top, behavior: props.scrollBehavior });
+        scrollAction$.subscribe(({ target, offset }: ScrollAction) => {
+          target.scrollTo({ ...offset, behavior: props.scrollBehavior });
         });
       })
     );
 
+    const contentSize = useObservable(contentSize$);
+    const rootStyles = computed<StyleValue>(() =>
+      Object.fromEntries([
+        ...Object.entries(contentSize.value ?? {}).map(([property, value]) => [
+          property,
+          value + "px",
+        ]),
+        ["placeContent", "start"],
+      ])
+    );
+
     return {
       rootRef,
       probeRef,
       buffer: useObservable(buffer$),
-      contentHeight: useObservable(contentHeight$),
+      rootStyles,
     };
   },
 });

src/demo/App.vue

@@ -1,42 +1,46 @@
 <template>
-  <Header />
-
-  <Grid
-    :length="length"
-    :pageSize="pageSize"
-    :pageProvider="pageProvider"
-    :pageProviderDebounceTime="0"
-    :scrollTo="scrollTo"
-    :scrollBehavior="scrollBehavior"
-    :class="$style.grid"
-  >
-    <template v-slot:probe>
-      <ProductItem sizes="(min-width: 768px) 360px, 290px" />
-    </template>
-
-    <template v-slot:placeholder="{ style }">
-      <ProductItem :style="style" sizes="(min-width: 768px) 360px, 290px" />
-    </template>
-
-    <template v-slot:default="{ item, style }">
-      <ProductItem
-        :handle="item.handle"
-        :price="item.price * 100"
-        :compare-at-price="item.compare_at_price * 100"
-        :published-at="new Date(item.published_at)"
-        :style="style"
-        :master-src="item.product_image"
-        :initial-alt-master-src="true"
-        :alt="item.title"
-        sizes="(min-width: 768px) 360px, 290px"
-        :tags="item.tags"
-        :vendor="item.vendor"
-        :title="item.title"
-      />
-    </template>
-  </Grid>
-
-  <Control />
+  <div :class="$style.root">
+    <Header :class="$style.header" />
+
+    <div :class="$style.gridWrapper">
+      <Grid
+        :length="length"
+        :pageSize="pageSize"
+        :pageProvider="pageProvider"
+        :pageProviderDebounceTime="0"
+        :scrollTo="scrollTo"
+        :scrollBehavior="scrollBehavior"
+        :class="[$style.grid, $style[scrollMode]]"
+      >
+        <template v-slot:probe>
+          <ProductItem sizes="(min-width: 768px) 360px, 290px" />
+        </template>
+
+        <template v-slot:placeholder="{ style }">
+          <ProductItem :style="style" sizes="(min-width: 768px) 360px, 290px" />
+        </template>
+
+        <template v-slot:default="{ item, style }">
+          <ProductItem
+            :handle="item.handle"
+            :price="item.price * 100"
+            :compare-at-price="item.compare_at_price * 100"
+            :published-at="new Date(item.published_at)"
+            :style="style"
+            :master-src="item.product_image"
+            :initial-alt-master-src="true"
+            :alt="item.title"
+            sizes="(min-width: 768px) 360px, 290px"
+            :tags="item.tags"
+            :vendor="item.vendor"
+            :title="item.title"
+          />
+        </template>
+      </Grid>
+    </div>
+
+    <Control :class="$style.controls" />
+  </div>
 </template>
 
 <script lang="ts">
@@ -45,7 +49,14 @@ import Grid from "../Grid.vue";
 import Header from "./Header.vue";
 import Control from "./Control.vue";
 import ProductItem from "./ProductItem.vue";
-import { length, pageSize, pageProvider, scrollTo, scrollBehavior } from "./store";
+import {
+  length,
+  pageSize,
+  pageProvider,
+  scrollMode,
+  scrollTo,
+  scrollBehavior
+} from "./store";
 
 export default defineComponent({
   name: "App",
@@ -54,6 +65,7 @@ export default defineComponent({
     length,
     pageSize,
     pageProvider,
+    scrollMode,
     scrollTo,
     scrollBehavior,
   }),
@@ -83,61 +95,106 @@ body {
   background-color: var(--color-white);
 }
 
+.root {
+  display: grid;
+  grid-template: "header" "gridWrapper" 1fr "controls";
+  height: 100vh;
+}
+
+.header {
+  grid-area: header;
+}
+
+.gridWrapper {
+  grid-area: gridWrapper;
+  height: 100%;
+  overflow: auto;
+}
+
+.controls {
+  grid-area: controls;
+}
+
 .grid {
   display: grid;
   padding: 0 1rem;
   grid-gap: 2rem;
-  grid-template-columns: repeat(2, 1fr);
   place-items: start stretch;
+  box-sizing: content-box;
+}
+
+.grid.vertical {
+  grid-template-columns: repeat(2, 1fr);
+}
+
+.grid.horizontal {
+  grid-auto-flow: column;
+  grid-template-columns: 200px;
+  grid-template-rows: repeat(2, 1fr);
 }
 
 @media (min-width: 760px) {
   .grid {
     padding: 1.5rem;
     grid-gap: 3rem;
+  }
+
+  .grid.vertical {
     grid-template-columns: repeat(3, 1fr);
   }
 }
 
 @media (min-width: 1140px) {
-  .grid {
+  .grid.vertical {
     grid-template-columns: repeat(4, 1fr);
   }
 }
 
 @media (min-width: 1520px) {
-  .grid {
+  .grid.vertical {
     grid-template-columns: repeat(5, 1fr);
   }
 }
 
 @media (min-width: 1900px) {
-  .grid {
+  .grid.vertical {
     grid-template-columns: repeat(6, 1fr);
   }
 }
 
 @media (min-width: 2280px) {
-  .grid {
+  .grid.vertical {
     grid-template-columns: repeat(7, 1fr);
   }
 }
 
 @media (min-width: 2660px) {
-  .grid {
+  .grid.vertical {
     grid-template-columns: repeat(8, 1fr);
   }
 }
 
 @media (min-width: 3040px) {
-  .grid {
+  .grid.vertical {
     grid-template-columns: repeat(9, 1fr);
   }
 }
 
 @media (min-width: 3420px) {
-  .grid {
+  .grid.vertical {
     grid-template-columns: repeat(10, 1fr);
   }
 }
+
+@media (min-height: 721px) {
+  .grid.horizontal {
+    grid-template-rows: repeat(3, 1fr);
+  }
+}
+
+@media (min-height: 1081px) {
+  .grid.horizontal {
+    grid-template-rows: repeat(4, 1fr);
+  }
+}
 </style>