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ngrx-entity-relationship

library1.7.1jsnpmunverified

An ORM-like library for managing entity relationships in NgRx applications built on top of @ngrx/entity and @ngrx/data. Current stable version: 1.7.1. Release cadence is intermittent with patch updates as needed. Key differentiators: provides a declarative API to define relationships (hasOne, hasMany, belongsTo) between entities, automatically resolves nested data, and integrates with @ngrx/entity selectors. It simplifies the boilerplate of normalizing and denormalizing relational data in the store. Supports Angular 12+ and RxJS 6+; TypeScript types are included. Alternative to manual selector composition or libraries like ngrx-normalizr.

database

npm install ngrx-entity-relationship

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · NGRX-ENTITY-RELATI

ngrx-entity-relationship

databasejavascriptv1.7.1

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

selectEntity

✓ import { selectEntity } from 'ngrx-entity-relationship'

Main selector function for fetching an entity with its relationships.

rootEntities

✓ import { rootEntities } from 'ngrx-entity-relationship'

Function to define root entity selectors for relationship chaining.

rootEntity

✓ import { rootEntity } from 'ngrx-entity-relationship'

Function to define a single root entity selector.

Defines a root entity relationship with a hasMany relation and uses selectEntity to fetch it.

import { select, Store } from '@ngrx/store'; import { rootEntity, selectEntity, hasMany, hasOne } from 'ngrx-entity-relationship'; // Define relationships const authorRel = rootEntity( (state: any) => state.authors, 'id', { books: hasMany( (state: any) => state.books, 'authorId', ), }, ); // In component class MyComponent { author$ = this.store.pipe( select(selectEntity(authorRel, 'authorId')), ); constructor(private store: Store) {} }

Debug

Known issues

gotchaThe library uses memoization based on function identity. Ensure relationship definitions are stable references to avoid unnecessary re-renders.

fix

Define relationships outside of component class or use memoization techniques (e.g., store in a constant or use a factory with shared references).

affects: >=1.0.0

breakingIn v2 (future) the API for rootEntities may change to require explicit entity adapters. Check changelog on migration.

fix

Update to use adapter selectors provided by @ngrx/entity.

affects: >=2.0.0

deprecatedUsing flat selectors like 'selectEntitiesArray' is deprecated in favor of 'selectEntities' with proper mapping.

fix

Replace selectEntitiesArray with selectEntities and map the result if needed.

affects: >=1.5.0

Errors

Common errors & fixes

TypeError: Cannot read property 'ids' of undefined

The entity adapter state is not properly initialized in the store (e.g., missing initial state).

fix

Ensure the reducer for the entity state is created using the adapter's initial state (e.g., adapter.getInitialState()).

Error: The relationship 'books' is not defined for the given root entity

Typo in relationship name or missing relationship definition in the root entity object.

fix

Check that the relationship name matches exactly the key in the rootEntity config object.

NullInjectorError: No provider for Store!

The NgRx Store module is not imported in the root module/standalone component.

fix

Add StoreModule.forRoot({}) to your imports or provide the store in standalone bootstrap.

Upgrade

Version history

1.7.1latest on npm

Audit

Dependencies

@ngrx/entityrequiredPEER dependency: used for entity state management

@ngrx/storerequiredPEER dependency: used for state selectors

rxjsrequiredPEER dependency: used for reactive streams

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/satanTime/ngrx-entity-relationship ↗

packagengrx-entity-relationship ↗

homepagehttps://ngrx-entity-relationship.sudo.eu ↗