refactor(series): extract loadPublicSeries helper

server/utils/loadSeries.js

@@ -0,0 +1,47 @@
+import Series from '../models/series.js'
+import { connectDB } from './mongoose.js'
+
+/**
+ * Load a series by ObjectId, string id, or slug for public endpoints.
+ * Series has three identifier fields (`_id`, `id`, `slug`); this helper
+ * builds the same conditional `$or` query the call sites would otherwise
+ * inline. No isVisible gate today (parity with existing call-site behavior).
+ *
+ * @param {Object} reqEvent - h3 event (reserved for future auth/cookie access)
+ * @param {String} identifier - ObjectId string, string id, or slug
+ * @param {Object} [options]
+ * @param {Boolean} [options.lean] - apply .lean() to the query
+ * @param {String} [options.select] - apply .select() to the query
+ * @param {Boolean} [options.allowMissing] - return null instead of throwing 404 on miss
+ * @returns {Promise<Object|null>} the series document, or null if allowMissing and not found
+ */
+export async function loadPublicSeries(reqEvent, identifier, options = {}) {
+  if (!identifier) {
+    throw createError({
+      statusCode: 400,
+      statusMessage: 'Series identifier is required'
+    })
+  }
+
+  await connectDB()
+
+  const { lean = false, select = null, allowMissing = false } = options
+
+  const isObjectId = /^[0-9a-fA-F]{24}$/.test(identifier)
+  const seriesQuery = isObjectId
+    ? { $or: [{ _id: identifier }, { id: identifier }, { slug: identifier }] }
+    : { $or: [{ id: identifier }, { slug: identifier }] }
+
+  let query = Series.findOne(seriesQuery)
+  if (select) query = query.select(select)
+  if (lean) query = query.lean()
+
+  const series = await query
+
+  if (!series) {
+    if (allowMissing) return null
+    throw createError({ statusCode: 404, statusMessage: 'Series not found' })
+  }
+
+  return series
+}