DefaultDataAdapter

import { DefaultDataAdapter } from '@signaldb/core'

Keeps every collection in memory on the main thread and answers queries from there. Writes are applied immediately and persisted in the background, which is what makes an optimistic UI fall out for free.

This is the adapter to use unless you have a reason not to, and the one a collection constructed without an adapter uses.

Usage

import { Collection, DefaultDataAdapter } from '@signaldb/core'
import createLocalStorageAdapter from '@signaldb/localstorage'

const dataAdapter = new DefaultDataAdapter({
  storage: name => createLocalStorageAdapter(name),
})

const Posts = new Collection('posts', dataAdapter)
const Authors = new Collection('authors', dataAdapter)

Without a storage function the data lives only in memory and is gone on reload — useful for tests and for data you derive rather than keep.

Options

new DefaultDataAdapter(options?: {
  storage?: (name: string) => StorageAdapter<any, any> | undefined
  onError?: (name: string, error: Error) => void
})

• storage: Called once per collection with the collection's name, and returns the storage adapter that collection persists to. Return undefined to keep a particular collection in memory only.
• onError: Called when setting up a collection's storage adapter or loading its stored items fails; without it, the error is logged with console.error. The collection's ready() then rejects with the same error and isReady() stays false, while the collection keeps working in memory. A write whose storage operation fails rejects its own promise instead.

Queries are synchronous

Because the data is in memory, find().fetch() returns the result directly and Cursor#isLoading() is never true after the collection is ready. Waiting for collection.ready() is still necessary before the first read: until the storage adapter has loaded, the collection is empty, and an empty result is indistinguishable from a real one.

Indices

The indices a collection declares are used here. A selector no index covers is answered by scanning the collection in memory — fine while it is small, and the thing to fix when it grows. See what this means for your collections.