The **@js-entity-repos/core** package supplies a set of standard TypeScript/JavaScript interfaces, utilities, and test suites that define the contract for “entity repositories” – a repository‑pattern implementation that abstracts data access for domain entities. It’s aimed at library and application developers who need a lightweight, cursor‑based pagination and localized error handling alternative to frameworks like FeathersJS, and who want a solid, test‑driven foundation for building concrete repository implementations.