A module for creating shared storage for Bedrock Web Apps. The design requires
stored objects to have only one instance in memory. The objects may be backed
by a persistent storage layer such as localStorage
or IndexedDB
. Whether
or not persistent storage is used is determined by the underlying engine
associated with a particular Store
instance.
It is important to note that even if a persistent storage mechanism is used,
any objects retrieved from storage via the Store
API will have only one
in-memory copy, ensuring that frontend components will share the same
instance. That is to say that a naive implementation of a Store
engine
that simply maps the API onto, for example, localForage
or localStorage
would break this guarantee. There must also be a shared memory layer.
npm install bedrock-web-store
The most common setup for a Web App is to use a single instance of shared
storage across the application. Namespacing can be achieved via the id
parameter.
In setup file:
import {store, MemoryEngine} from 'bedrock-web-store';
store.setEngine({engine: new MemoryEngine()});
In file 1:
import {store} from 'bedrock-web-store';
const foo = {a: 1, b: 2};
store.create({id: '123', object: foo});
In file 2:
import {store} from 'bedrock-web-store';
const foo = store.get({id: '123'});
console.log(foo.a);
// yields "1"
More complex Web Apps may have a reason for partitioning storage into different
instances. This could be done for namespacing purposes where id
s would
otherwise clash or because different storage engines are needed for different
purposes. In this case, the Store
class can be imported and multiple
instances (potentially with different engines) can be created and managed by
the Web App.
In custom myStores.js
:
import {Store, MemoryEngine} from 'bedrock-web-store';
export const stores = {};
stores.foos = new Store({engine: new MemoryEngine()});
stores.bars = new Store({engine: new MemoryEngine()});
In file 1:
import {stores} from './myStores.js';
const foo = {a: 1, b: 2};
stores.foos.create({id: '123', object: foo});
// ...
In file 2:
import {stores} from './myStores.js';
const foo = stores.foos.get({id: '123'});
// same `foo` as file 1
// ...
const bar = stores.bars.get({id: '123'});
// `bar` is undefined