@weasel-js/storage

Keyed storage behind one async interface, StorageAdapter, with adapters for IndexedDB, localStorage, sessionStorage, the URL hash and memory. openRecords loads every record under a prefix into a RecordCache: reads are synchronous from memory, writes land in memory at once and reach storage on a debounce, and changes other tabs make arrive as remote changes.

Adapters that can read synchronously (localStorage, sessionStorage, memory) also implement listSync, and openRecordsSync opens a cache from one with no await.

A cache whose first read fails opens empty with writable false, and reads again on a backoff (retryMs, doubling to retryMaxMs; retryMs: false turns that off). cache.read() tries at once, and cache.whenRead() resolves once a read has landed. When a read lands, the cache reports the records as remote changes and starts writing, beginning with whatever was set while it waited; those writes win over what it read.

A write storage rejects stays queued and is sent again on the same backoff, and flush() resolves false until it lands. While a write is queued or on its way, another writer's change to that record is ignored. With retryMs: false a rejected write waits for the next flush.

defaultStorage() is IndexedDB under the database 'weasel', or localStorage, with a warning, where IndexedDB will not open; it chooses once per page. fallbackStorage(preferred, fallback, label) makes the same choice between any two adapters, and createDefaultStorage(preferred, label) builds a defaultStorage of your own over a different preferred adapter, such as IndexedDB under another database.