dataloaders.go

func newAuthorsByAgentID(ctx context.Context, repo pg.Repository) *AuthorSliceLoader {
	return NewAuthorSliceLoader(AuthorSliceLoaderConfig{
		MaxBatch: 100,
		Wait:     5 * time.Millisecond,
		Fetch: func(agentIDs []int64) ([][]pg.Author, []error) {
			// db query
			res, err := repo.ListAuthorsByAgentIDs(ctx, agentIDs)
			if err != nil {
				return nil, []error{err}
			}
			// group
			groupByAgentID := make(map[int64][]pg.Author, len(agentIDs))
			for _, r := range res {
				groupByAgentID[r.AgentID] = append(groupByAgentID[r.AgentID], r)
			}
			// order
			result := make([][]pg.Author, len(agentIDs))
			for i, agentID := range agentIDs {
				result[i] = groupByAgentID[agentID]
			}
			return result, nil
		},
	})
}