Entity-state-adapter

Entity State adapter for managing record collections (based on @ngrx/entitywork with redux and useReducer hooks

Entity-state-adapter provides an API to manipulate and query entity collections.

Reduces boilerplate for creating reducers that manage a collection of models. Provides performant CRUD operations for managing entity collections. Extensible adapters for selecting entity information.

usage

Installation

npm i entity-state-adapter

or

yarn add entity-state-adapter

The initialisation

import { createEntityAdapter } from "entity-state-adapter";

export function selectUserId(a) {
    //In this case this would be optional since primary key is id
    return a.id;
}

export function sortByName(a, b): number {
    return a.name.localeCompare(b.name);
}

export const adapter = createEntityAdapter({
    selectId: selectUserId,
    sortComparer: sortByName
});

Adapter Collection Methods

The entity adapter also provides methods for operations against an entity. These methods can change one to many records at a time. Each method returns the newly modified state if changes were made and the same state if no changes were made.

• addOne: Add one entity to the collection
• addMany: Add multiple entities to the collection
• addAll: Replace current collection with provided collection
• removeOne: Remove one entity from the collection
• removeMany: Remove multiple entities from the collection, by id or by predicate
• removeAll: Clear entity collection
• updateOne: Update one entity in the collection
• updateMany: Update multiple entities in the collection
• upsertOne: Add or Update one entity in the collection
• upsertMany: Add or Update multiple entities in the collection
• map: Update multiple entities in the collection by defining a map function, similar to Array.map

The initialState is always required and must be create with adapter.getInitialState({otherState: optional})

export const userInitialState = adapter.getInitialState({});

const [users, dispatch] = useReducer(
    userReducer,
    userInitialState,
    state => state
);

And the reducer

export function userReducer(state, action) {
    switch (action.type) {
        case ADD_ALL:
            return adapter.addMany(action.payload.users, state);

        case ADD_ONE:
            return adapter.addOne(action.payload.user, state);

        case UPSERT_ONE:
            return adapter.upsertOne(action.payload.user, state);

        case UPSERT_ALL:
            return adapter.upsertUsers(action.payload.users, state);
        case UPDATE_ONE:
            return adapter.updateOne(action.payload.user, state);

        case UPDATE_ALL:
            return adapter.updateMany(action.payload.users, state);

        case MAP_ALL:
            return adapter.map(action.payload.entityMap, state);

        case DELETE_ONE:
            return adapter.removeOne(action.payload.id, state);

        case DELETE_ALL_BY_IDS:
            return adapter.removeMany(action.payload.ids, state);

        case DELETE_ALL_BY_PREDICAT:
            return adapter.removeMany(action.payload.predicate, state);

        case CLEAR_SELECTED_USER:
            return adapter.removeAll({ ...state, selectedUserId: null });

        default:
            return state;
    }
}

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