Storage module (`@sandlada/document-context/storage`)

Persistent state with hydration precedence, schema migration, fault tolerance, and cross-tab synchronization. Composed in Phase 1 via withStorage, resolved during mount.

Operator

Export	Purpose
withStorage(options)	Configures adapter, key, hydrationStrategy, crossTabSync, version, and migrate.

import { createContext, pipe, mount } from '@sandlada/document-context/core'
import { withStorage } from '@sandlada/document-context/storage'

const blueprint = pipe(
    createContext({ theme: 'light' as 'light' | 'dark' }),
    withStorage({
        adapter: 'localStorage',
        key: 'app-theme',
        hydrationStrategy: 'storageFirst',
        version: 2,
        migrate: (oldData: unknown, oldVersion: number) => ({ ...(oldData as object) })
    })
)
const session = mount(blueprint)(document.documentElement)

Hydration strategies

Strategy	Precedence
storageFirst (default)	Persisted state wins, falls back to blueprint seed.
domFirst	DOM attributes win (currently resolved like merge).
blueprintFirst	Blueprint seed wins.
merge	Shallow merge of persisted state over the seed.

Adapters and sync

Built-in localStorage and sessionStorage adapters plus custom sync/async adapters. Corrupted payloads emit InvalidStorageDataError to readErrorStream and fall back to the seed instead of throwing. Cross-tab updates propagate via the storage event and BroadcastChannel, coordinated with Web Locks.