react-native-onyx/dist/OnyxSnapshotCache.d.ts

State management for React Native

import type { OnyxKey, OnyxValue } from './types';
import type { UseOnyxOptions, UseOnyxResult, UseOnyxSelector } from './useOnyx';
/**
 * Manages snapshot caching for useOnyx hook performance optimization.
 * Handles selector function tracking and memoized getSnapshot results.
 */
declare class OnyxSnapshotCache {
    /**
     * Snapshot cache is a two-level map. The top-level keys are Onyx keys. The top-level values maps.
     * The second-level keys are a custom composite string defined by this.registerConsumer. These represent a unique useOnyx config, which is not fully represented by the Onyx key alone.
     * The reason we have two levels is for performance: not to make cache access faster, but to make cache invalidation faster.
     * We can invalidate the snapshot cache for a given Onyx key with one map.delete operation on the top-level map, rather than having to loop through a large single-level map and delete any matching keys.
     */
    private snapshotCache;
    /**
     * Maps selector functions to unique IDs for cache key generation
     */
    private selectorIDMap;
    /**
     * Counter for generating incremental selector IDs
     */
    private selectorIDCounter;
    /**
     * Reference counting for cache keys to enable automatic cleanup.
     * Maps cache key (string) to number of consumers using it.
     */
    private cacheKeyRefCounts;
    constructor();
    /**
     * Generate unique ID for selector functions using incrementing numbers
     */
    getSelectorID<TKey extends OnyxKey, TReturnValue>(selector: UseOnyxSelector<TKey, TReturnValue>): number;
    /**
     * Register a consumer for a cache key and return the cache key.
     * Generates cache key and increments reference counter.
     *
     * The properties used to generate the cache key are handpicked for performance reasons and
     * according to their purpose and effect they produce in the useOnyx hook behavior:
     *
     * - `selector`: Different selectors produce different results, so each selector needs its own cache entry
     * - `initWithStoredValues`: This flag changes the initial loading behavior and affects the returned fetch status
     * - `allowStaleData`: Controls whether stale data can be returned during pending merges, affecting result timing
     * - `canBeMissing`: Determines logging behavior for missing data, but doesn't affect the actual data returned
     *
     * Other options like `canEvict`, `reuseConnection`, and `allowDynamicKey` don't affect the data transformation
     * or timing behavior of getSnapshot, so they're excluded from the cache key for better cache hit rates.
     */
    registerConsumer<TKey extends OnyxKey, TReturnValue>(options: Pick<UseOnyxOptions<TKey, TReturnValue>, 'selector' | 'initWithStoredValues' | 'allowStaleData' | 'canBeMissing'>): string;
    /**
     * Deregister a consumer for a cache key.
     * Decrements reference counter and removes cache entry if no consumers remain.
     */
    deregisterConsumer(key: OnyxKey, cacheKey: string): void;
    /**
     * Get cached snapshot result for a key and cache key combination
     */
    getCachedResult<TResult extends UseOnyxResult<OnyxValue<OnyxKey>>>(key: OnyxKey, cacheKey: string): TResult | undefined;
    /**
     * Set cached snapshot result for a key and cache key combination
     */
    setCachedResult<TResult extends UseOnyxResult<OnyxValue<OnyxKey>>>(key: OnyxKey, cacheKey: string, result: TResult): void;
    /**
     * Selective cache invalidation to prevent data unavailability
     * Collection members invalidate upward, collections don't cascade downward
     */
    invalidateForKey(keyToInvalidate: OnyxKey): void;
    /**
     * Clear all snapshot cache
     */
    clear(): void;
    /**
     * Clear selector ID mappings (useful for testing)
     */
    clearSelectorIds(): void;
}
declare const onyxSnapshotCache: OnyxSnapshotCache;
export default onyxSnapshotCache;
export { OnyxSnapshotCache };