fix: 修复笔记 YAML 标签保存与索引重建一致性

frontend/src/utils/noteMetadata.ts

@@ -0,0 +1,54 @@
+import { isMap, isScalar, isSeq, parseDocument } from 'yaml'
+
+export interface NoteMetadata {
+  prefix: string
+  yaml: string
+  body: string
+  title: string
+  tags: string[]
+  hasTags: boolean
+}
+
+function parseProperties(yaml: string) {
+  const document = parseDocument(yaml)
+  // Unsupported YAML stays available in source mode without partial rewriting.
+  if (document.errors.length || document.warnings.length || !isMap(document.contents)) return null
+  return document
+}
+
+export function splitNoteMetadata(source: string): NoteMetadata | null {
+  const match = source.match(/^\uFEFF?(---|\*\*\*)[ \t]*\r?\n([\s\S]*?)\r?\n(?:-{3,}|\.\.\.)[ \t]*(?:\r?\n|$)/)
+  if (!match) return null
+  const yaml = match[2]!
+  const document = parseProperties(yaml)
+  if (!document || (!document.has('title') && !document.has('tags'))) return null
+  const title = document.get('title') ?? ''
+  if (typeof title !== 'string') return null
+  const tagNode = document.get('tags', true)
+  let tags: string[] = []
+  if (isSeq(tagNode)) {
+    // Do not remove anchored list items that other properties may reference.
+    if (!tagNode.items.every(item => isScalar(item) && typeof item.value === 'string' && !item.anchor)) return null
+    tags = tagNode.items.map(item => (item as { value: string }).value)
+  } else if (isScalar(tagNode)) {
+    if (typeof tagNode.value === 'string') tags = tagNode.value.split(',').map(tag => tag.trim()).filter(Boolean)
+    else if (tagNode.value !== null) return null
+  } else if (tagNode !== undefined) return null
+  return { prefix: match[0], yaml, body: source.slice(match[0].length), title, tags, hasTags: document.has('tags') }
+}
+
+export function updateMetadataTags(metadata: NoteMetadata, tags: string[]): string {
+  const document = parseProperties(metadata.yaml)
+  if (!document) throw new Error('Invalid note metadata')
+  const previous = document.get('tags', true)
+  const replacement = document.createNode([...new Set(tags)])
+  if (isScalar(previous) || isSeq(previous)) {
+    replacement.anchor = previous.anchor
+    replacement.comment = previous.comment
+    replacement.commentBefore = previous.commentBefore
+  }
+  document.set('tags', replacement)
+  const newline = metadata.prefix.includes('\r\n') ? '\r\n' : '\n'
+  const prefix = `---\n${document.toString()}---\n`.replace(/\n/g, newline)
+  return (metadata.prefix.startsWith('\uFEFF') ? '\uFEFF' : '') + prefix
+}