DataLoader

RU: DataLoader

A utility library (originally by Facebook) that coalesces individual .load(key) calls made during one event-loop tick into a single batched call to a user-supplied batchLoadFn, and caches results for the lifetime of that request. It collapses the N+1 query problem in GraphQL resolvers into two round-trips — one for the parent list and one batched fetch for all child keys.