refactor(markdown): extract post-render effects into composable

Four components duplicated the watch -> nextTick -> listenToClick -> runTikz
shape. Collapse to useMarkdownPostRender, which also accepts optional flags
for Mermaid, Shikiji and image hydration so StackedNote no longer needs its
own inline conditional chain.

src/components/FluxNote.vue

@@ -1,5 +1,5 @@
 <script lang="ts" setup>
-import { computed, nextTick, onMounted, onUnmounted, toRefs, watch } from "vue"
+import { computed, onMounted, onUnmounted, toRefs, watch } from "vue"
 
 import HeaderNote from "@/components/HeaderNote.vue"
 import SignInGithub from "@/components/SignInGithub.vue"
@@ -7,7 +7,8 @@ import SkeletonLoader from "@/components/SkeletonLoader.vue"
 import StackedNote from "@/components/StackedNote.vue"
 import { useGitHubLogin } from "@/hooks/useGitHubLogin.hook"
 import { useLinks } from "@/hooks/useLinks.hook"
-import { markdownBuilder, runTikz } from "@/hooks/useMarkdown.hook"
+import { markdownBuilder } from "@/hooks/useMarkdown.hook"
+import { useMarkdownPostRender } from "@/hooks/useMarkdownPostRender.hook"
 import { useNoteView } from "@/hooks/useNoteView.hook"
 import { useResizeContainer } from "@/hooks/useResizeContainer.hook"
 import { useRouteQueryStackedNotes } from "@/hooks/useRouteQueryStackedNotes.hook"
@@ -59,15 +60,10 @@ const renderedContent = computed(() =>
 const isLoading = computed(() => renderedContent.value === undefined)
 const hasContent = computed(() => !!renderedContent.value)
 
-watch(
-  renderedContent,
-  async () => {
-    await nextTick()
-    listenToClick()
-    void runTikz(".note-display .tikz")
-  },
-  { immediate: true }
-)
+useMarkdownPostRender(renderedContent, () => ".note-display", {
+  onReady: () => listenToClick(),
+  tikz: true
+})
 
 watch(
   [refProps.user, refProps.repo],

src/components/StackedNote.vue

@@ -2,7 +2,6 @@
 import {
   computed,
   defineAsyncComponent,
-  nextTick,
   onMounted,
   ref,
   watch
@@ -11,14 +10,9 @@ import {
 import { useEditionMode } from "@/hooks/useEditionMode"
 import { useFile } from "@/hooks/useFile.hook"
 import { useGitHubContent } from "@/hooks/useGitHubContent.hook"
-import { useImages } from "@/hooks/useImages.hook"
 import { useLinks } from "@/hooks/useLinks.hook"
-import {
-  renderCodeFile,
-  runMermaid,
-  runTikz,
-  useShikiji
-} from "@/hooks/useMarkdown.hook"
+import { renderCodeFile } from "@/hooks/useMarkdown.hook"
+import { useMarkdownPostRender } from "@/hooks/useMarkdownPostRender.hook"
 import { useNoteFreshness } from "@/hooks/useNoteFreshness.hook"
 import { useNoteOverlay } from "@/hooks/useNoteOverlay.hook"
 import { useRouteQueryStackedNotes } from "@/hooks/useRouteQueryStackedNotes.hook"
@@ -145,30 +139,14 @@ watch(
 
 const { mode, toggleMode } = useEditionMode()
 
-watch([content, mode], () => {
-  if (!content.value) {
-    return
-  }
-
-  nextTick(() => {
-    listenToClick()
-
-    if (/\!\[.*?\]\(.*?\)/.test(rawContent.value)) {
-      useImages(props.sha)
-    }
-
-    if (rawContent.value.includes("```mermaid")) {
-      runMermaid(`.note-${sha.value} .mermaid`)
-    }
-
-    if (rawContent.value.includes("```tikz")) {
-      void runTikz(`.note-${sha.value} .tikz`)
-    }
-
-    if (isMarkdown.value && rawContent.value.includes("```")) {
-      useShikiji()
-    }
-  })
+useMarkdownPostRender(content, () => `.note-${sha.value}`, {
+  onReady: () => listenToClick(),
+  tikz: true,
+  mermaid: () => rawContent.value.includes("```mermaid"),
+  shikiji: () => isMarkdown.value && rawContent.value.includes("```"),
+  images: () =>
+    /\!\[.*?\]\(.*?\)/.test(rawContent.value) ? props.sha : null,
+  triggers: [mode]
 })
 
 const performSave = async (overrideSha?: string) => {

src/components/StackedPublicNote.vue

@@ -1,11 +1,12 @@
 <script lang="ts" setup>
 import { computedAsync } from "@vueuse/core"
-import { computed, nextTick, ref, watch } from "vue"
+import { computed, ref, watch } from "vue"
 import { useRoute } from "vue-router"
 
 import SkeletonLoader from "@/components/SkeletonLoader.vue"
 import { useATProtoLinks } from "@/hooks/useATProtoLinks.hook"
-import { markdownBuilder, runTikz } from "@/hooks/useMarkdown.hook"
+import { markdownBuilder } from "@/hooks/useMarkdown.hook"
+import { useMarkdownPostRender } from "@/hooks/useMarkdownPostRender.hook"
 import { useNoteOverlay } from "@/hooks/useNoteOverlay.hook"
 import { useRouteQueryStackedNotes } from "@/hooks/useRouteQueryStackedNotes.hook"
 import { getAuthor } from "@/modules/atproto/getAuthor"
@@ -76,15 +77,10 @@ const content = computed(() =>
     : ""
 )
 
-watch(
-  content,
-  async () => {
-    await nextTick()
-    listenToClick()
-    void runTikz(`.note-${classNameId.value} .tikz`)
-  },
-  { immediate: true }
-)
+useMarkdownPostRender(content, () => `.note-${classNameId.value}`, {
+  onReady: () => listenToClick(),
+  tikz: true
+})
 </script>
 
 <template>

src/hooks/useMarkdownPostRender.hook.ts

@@ -0,0 +1,54 @@
+import { nextTick, type Ref, toValue, watch } from "vue"
+
+import { useImages } from "@/hooks/useImages.hook"
+import {
+  runMermaid,
+  runTikz,
+  useShikiji
+} from "@/hooks/useMarkdown.hook"
+
+interface MarkdownPostRenderOptions {
+  onReady?: () => void
+  tikz?: boolean
+  mermaid?: () => boolean
+  shikiji?: () => boolean
+  images?: () => string | null | undefined
+  triggers?: Ref<unknown>[]
+}
+
+export const useMarkdownPostRender = (
+  contentRef: Ref<unknown>,
+  scopeSelector: () => string,
+  options: MarkdownPostRenderOptions = {}
+) => {
+  const sources = [contentRef, ...(options.triggers ?? [])]
+
+  watch(
+    sources,
+    async () => {
+      if (!toValue(contentRef)) return
+      await nextTick()
+      options.onReady?.()
+
+      const scope = scopeSelector()
+
+      if (options.tikz) {
+        void runTikz(`${scope} .tikz`)
+      }
+
+      if (options.mermaid?.()) {
+        runMermaid(`${scope} .mermaid`)
+      }
+
+      if (options.shikiji?.()) {
+        void useShikiji()
+      }
+
+      const imagesSha = options.images?.()
+      if (imagesSha) {
+        useImages(imagesSha)
+      }
+    },
+    { immediate: true }
+  )
+}

src/views/PublicNoteView.vue

@@ -1,7 +1,7 @@
 <script setup lang="ts">
 import { computedAsync } from "@vueuse/core"
 import { useTitle } from "@vueuse/core"
-import { computed, nextTick, ref, watch } from "vue"
+import { computed, ref, watch } from "vue"
 import { useRouter } from "vue-router"
 
 import HomeButton from "@/components/HomeButton.vue"
@@ -9,7 +9,8 @@ import SkeletonLoader from "@/components/SkeletonLoader.vue"
 import StackedPublicNote from "@/components/StackedPublicNote.vue"
 import ThemeSwap from "@/components/ThemeSwap.vue"
 import { useATProtoLinks } from "@/hooks/useATProtoLinks.hook"
-import { markdownBuilder, runTikz } from "@/hooks/useMarkdown.hook"
+import { markdownBuilder } from "@/hooks/useMarkdown.hook"
+import { useMarkdownPostRender } from "@/hooks/useMarkdownPostRender.hook"
 import { useResizeContainer } from "@/hooks/useResizeContainer.hook"
 import { useRouteQueryStackedNotes } from "@/hooks/useRouteQueryStackedNotes.hook"
 import { getAuthor } from "@/modules/atproto/getAuthor"
@@ -115,15 +116,10 @@ const { stackedNotes, scrollToFocusedNote } = useRouteQueryStackedNotes()
 const { listenToClick } = useATProtoLinks("note-display", { mainNoteId })
 useResizeContainer("note-container", stackedNotes)
 
-watch(
-  content,
-  async () => {
-    await nextTick()
-    listenToClick()
-    void runTikz(".public-note-view .note-display .tikz")
-  },
-  { immediate: true }
-)
+useMarkdownPostRender(content, () => ".public-note-view .note-display", {
+  onReady: () => listenToClick(),
+  tikz: true
+})
 </script>
 
 <template>