API: configurePersistenceEngine

Global configuration for persisting state fields in mobx-chunk. Plug any storage engine by providing CRUD methods for string-based keys and values.

function configurePersistenceEngine(
  engine: PersistenceEngine
): void

PersistenceEngine Interface

interface PersistenceEngine {
  /**
   * Clear all stored entries or scoped entries if key provided.
   * @param key Optional prefix or specific key to clear.
   * */
  clear: (key?: string) => void | Promise<void>;

  /**
   * Retrieve a stored string by key.
   * Returns either a string or a promise resolving to a string or null.
   */
  get: (key: string) => string | Promise<string | null>;

  /**
   * Remove a stored entry by key.
   */
  remove: (key: string) => void | Promise<void>;

  /**
   * Store a string value under a key.
   */
  set: (key: string, value: string) => void | Promise<void>;
}

Usage

Call configurePersistenceEngine once, preferably in your app’s root or entry point before any createChunk calls that use persist:

import { configurePersistenceEngine } from "mobx-chunk";

// Example: React Native MMKV
import { MMKV } from "react-native-mmkv";
const storage = new MMKV();

configurePersistenceEngine({
  clear: () => storage.clearAll(),
  get:    (key) => storage.getString(key),
  remove: (key) => storage.delete(key),
  set:    (key, value) => storage.set(key, value),
});

Behavior

• Read on Initialization: When a chunk with persist fields is created, stored values are read automatically and merged into the initial state.
• Write on Change: Whenever a set${Field} action updates a persisted field, the new value is serialized and saved via engine.set under a composed key: ${chunkName}:${field}.
• Remove on Deletion: If a persisted field is removed (e.g., set to undefined), engine.remove is called for the key.
• Clear All: Calling engine.clear() purges all keys. Some engines support namespaced clearing by passing a prefix.

Return Value

• void — there’s no return. After configuration, the engine is used under the hood by persisted chunks.

Use configurePersistenceEngine to integrate any storage solution (synchronous or asynchronous) for persisted fields across sessions.