feat(theme): add backTop button

packages/theme/src/client/components/BackToTop.vue

@@ -0,0 +1,63 @@
+<script lang="ts" setup>
+import { onMounted, onUnmounted, ref } from 'vue'
+import { scrollTo } from '../utils'
+import { BackTopIcon } from './icons'
+
+const opacity = ref<number>(0)
+const MAX_TOP = 300
+
+const canShow = (): void => {
+  if (__VUEPRESS_SSR__) return
+  opacity.value = document.documentElement.scrollTop >= MAX_TOP ? 1 : 0
+}
+
+const scrollToTop = (): void => {
+  scrollTo(document, 0)
+}
+
+onMounted(() => {
+  if (__VUEPRESS_SSR__) return
+  canShow()
+  window.addEventListener('scroll', canShow, false)
+})
+
+onUnmounted(() => {
+  if (__VUEPRESS_SSR__) return
+  window.removeEventListener('scroll', canShow)
+})
+</script>
+<template>
+  <div class="btn-back-top" :style="{ opacity: opacity }" @click="scrollToTop">
+    <BackTopIcon />
+  </div>
+</template>
+<style lang="scss">
+.btn-back-top {
+  position: fixed;
+  right: 3rem;
+  bottom: 3rem;
+  width: 3rem;
+  height: 3rem;
+  text-align: center;
+  padding: 0.75rem 0;
+  border-radius: 50%;
+  background-color: var(--c-bg-container);
+  box-shadow: var(--shadow-md);
+  cursor: pointer;
+  transition: opacity var(--t-color);
+  z-index: 99;
+
+  .back-top-icon {
+    width: 1.75rem;
+    height: 1.75rem;
+    color: var(--c-brand);
+    transition: color var(--t-color);
+  }
+
+  &:hover {
+    .back-top-icon {
+      color: var(--c-brand-light);
+    }
+  }
+}
+</style>

packages/theme/src/client/components/icons/icon.ts

@@ -64,3 +64,11 @@ export const ArrowRightIcon: FunctionalComponent = () =>
     })
   )
 ArrowRightIcon.displayName = 'ArrowRightIcon'
+
+export const BackTopIcon: FunctionalComponent = () =>
+  h(IconBase, { name: 'back-top', viewBox: '0 0 1024 1024' }, () =>
+    h('path', {
+      d: 'M832 64H192c-17.6 0-32 14.4-32 32s14.4 32 32 32h640c17.6 0 32-14.4 32-32s-14.4-32-32-32zM852.484 519.469L538.592 205.577a30.79 30.79 0 0 0-3.693-4.476c-6.241-6.241-14.556-9.258-22.899-9.09-8.343-0.168-16.658 2.849-22.899 9.09a30.778 30.778 0 0 0-3.693 4.476L171.419 519.566C164.449 525.448 160 534.228 160 544c0 0.058 0.004 0.115 0.004 0.172-0.124 8.285 2.899 16.529 9.096 22.727 6.202 6.202 14.453 9.224 22.743 9.096 0.066 0 0.131 0.005 0.197 0.005H352v320c0 35.2 28.8 64 64 64h192c35.2 0 64-28.8 64-64V576h160c0.058 0 0.115-0.004 0.172-0.004 8.285 0.124 16.529-2.899 22.727-9.096 6.198-6.198 9.22-14.442 9.096-22.727 0-0.058 0.004-0.115 0.004-0.172 0.001-9.826-4.489-18.65-11.515-24.532z',
+    })
+  )
+BackTopIcon.displayName = 'BackTopIcon'

packages/theme/src/client/layouts/Layout.vue

@@ -1,6 +1,7 @@
 <script setup lang="ts">
 import Archive from '@theme-plume/Archive.vue'
 import AsideNavbar from '@theme-plume/AsideNavbar.vue'
+import BackToTop from '@theme-plume/BackToTop.vue'
 import Category from '@theme-plume/Category.vue'
 import Home from '@theme-plume/Home.vue'
 import Navbar from '@theme-plume/Navbar.vue'
@@ -58,6 +59,7 @@ const pageMap = {
         </template>
       </Page>
     </slot>
+    <BackToTop />
     <slot name="footer">
       <PageFooter></PageFooter>
     </slot>