feat: basic parsing of post content

composables/content.ts

@@ -0,0 +1,72 @@
+import type { DefaultTreeAdapterMap } from 'parse5'
+import { parseFragment, serialize } from 'parse5'
+import type { VNode } from 'vue'
+import { Fragment, h } from 'vue'
+import { RouterLink } from 'vue-router'
+
+type Node = DefaultTreeAdapterMap['childNode']
+type Element = DefaultTreeAdapterMap['element']
+
+const UserLinkRE = /^https?:\/\/([^/]+)\/@([^/]+)$/
+const TagLinkRE = /^https?:\/\/([^/]+)\/tags\/([^/]+)$/
+
+export function defaultHandle(el: Element) {
+  // Redirect mentions to the user page
+  if (el.tagName === 'a' && el.attrs.find(i => i.name === 'class' && i.value.includes('mention'))) {
+    const href = el.attrs.find(i => i.name === 'href')
+    if (href) {
+      const matchUser = href.value.match(UserLinkRE)
+      if (matchUser) {
+        const [, server, username] = matchUser
+        href.value = `/@${username}@${server}`
+      }
+      const matchTag = href.value.match(TagLinkRE)
+      if (matchTag) {
+        const [, , name] = matchTag
+        href.value = `/tags/${name}`
+      }
+    }
+  }
+  return el
+}
+
+export function contentToVNode(
+  content: string,
+  handle: (node: Element) => Element | undefined | null | void = defaultHandle,
+): VNode {
+  const tree = parseFragment(content)
+  return h(Fragment, tree.childNodes.map(n => treeToVNode(n, handle)))
+}
+
+export function treeToVNode(
+  input: Node,
+  handle: (node: Element) => Element | undefined | null | void = defaultHandle,
+): VNode | string | null {
+  if (input.nodeName === '#text')
+    // @ts-expect-error casing
+    return input.value
+
+  if ('childNodes' in input) {
+    const node = handle(input)
+    if (node == null)
+      return null
+
+    const attrs = Object.fromEntries(node.attrs.map(i => [i.name, i.value]))
+    if (node.nodeName === 'a' && (attrs.href?.startsWith('/') || attrs.href?.startsWith('.'))) {
+      attrs.to = attrs.href
+      delete attrs.href
+      delete attrs.target
+      return h(
+        RouterLink as any,
+        attrs,
+        node.childNodes.map(n => treeToVNode(n, handle)),
+      )
+    }
+    return h(
+      node.nodeName,
+      attrs,
+      node.childNodes.map(n => treeToVNode(n, handle)),
+    )
+  }
+  return null
+}