tieredStorage()

Creates a reactive tiered storage cache backed by CheckpointAdapters.

Each cached key is a state() store. On cache miss, tiers are tried in order (index 0 = hottest). Hits auto-promote to all faster tiers. Concurrent lookups for the same key share the same state instance (natural dedup).

Signature

function tieredStorage(
	adapters: CheckpointAdapter[],
	opts?: TieredStorageOptions,
): TieredStorageAdapter

Parameters

Parameter	Type	Description
adapters	CheckpointAdapter[]	Ordered CheckpointAdapters, hottest first.
opts	TieredStorageOptions	Optional configuration (maxSize, eviction policy).

Returns

TieredStorageAdapter — a reactive cache where each entry is a WritableStore.

Basic Usage

import { tieredStorage, memoryAdapter } from 'callbag-recharge/utils';
import { subscribe } from 'callbag-recharge/extra';

const storage = tieredStorage([memoryAdapter(), fileAdapter({ dir: ".cache" })], {
    maxSize: 100,
  });

const store = storage.load("key");   // WritableStore<unknown | undefined>
subscribe(store, v => console.log(v)); // reactive updates on cache changes