catalogTree = $apiService->getTextbookCatalog((int) $this->record->id, 'tree'); $seriesName = $this->record->series->name ?? null; $this->linkedPapers = SourcePaper::query() ->when($seriesName, fn ($query) => $query->where('textbook_series', $seriesName)) ->latest('updated_at') ->take(8) ->get() ->map(fn ($paper) => [ 'id' => $paper->id, 'title' => $paper->title ?: $paper->full_title ?: '未命名卷子', 'chapter' => $paper->chapter, 'grade' => $paper->grade, 'term' => $paper->term, 'source_type' => $paper->source_type, 'updated_at' => $paper->updated_at, ]) ->toArray(); } }