1277 lines
53 KiB
TypeScript
1277 lines
53 KiB
TypeScript
/**
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* @module LRUCache
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*/
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declare const TYPE: unique symbol;
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export type PosInt = number & {
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[TYPE]: 'Positive Integer';
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};
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export type Index = number & {
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[TYPE]: 'LRUCache Index';
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};
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export type UintArray = Uint8Array | Uint16Array | Uint32Array;
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export type NumberArray = UintArray | number[];
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declare class ZeroArray extends Array<number> {
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constructor(size: number);
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}
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export type { ZeroArray };
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export type { Stack };
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export type StackLike = Stack | Index[];
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declare class Stack {
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#private;
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heap: NumberArray;
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length: number;
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static create(max: number): StackLike;
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constructor(max: number, HeapCls: {
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new (n: number): NumberArray;
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});
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push(n: Index): void;
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pop(): Index;
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}
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/**
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* Promise representing an in-progress {@link LRUCache#fetch} call
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*/
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export type BackgroundFetch<V> = Promise<V | undefined> & {
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__returned: BackgroundFetch<V> | undefined;
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__abortController: AbortController;
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__staleWhileFetching: V | undefined;
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};
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export type DisposeTask<K, V> = [
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value: V,
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key: K,
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reason: LRUCache.DisposeReason
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];
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export declare namespace LRUCache {
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/**
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* An integer greater than 0, reflecting the calculated size of items
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*/
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type Size = number;
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/**
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* Integer greater than 0, representing some number of milliseconds, or the
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* time at which a TTL started counting from.
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*/
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type Milliseconds = number;
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/**
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* An integer greater than 0, reflecting a number of items
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*/
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type Count = number;
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/**
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* The reason why an item was removed from the cache, passed
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* to the {@link Disposer} methods.
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*
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* - `evict`: The item was evicted because it is the least recently used,
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* and the cache is full.
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* - `set`: A new value was set, overwriting the old value being disposed.
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* - `delete`: The item was explicitly deleted, either by calling
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* {@link LRUCache#delete}, {@link LRUCache#clear}, or
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* {@link LRUCache#set} with an undefined value.
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* - `expire`: The item was removed due to exceeding its TTL.
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* - `fetch`: A {@link OptionsBase#fetchMethod} operation returned
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* `undefined` or was aborted, causing the item to be deleted.
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*/
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type DisposeReason = 'evict' | 'set' | 'delete' | 'expire' | 'fetch';
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/**
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* A method called upon item removal, passed as the
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* {@link OptionsBase.dispose} and/or
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* {@link OptionsBase.disposeAfter} options.
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*/
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type Disposer<K, V> = (value: V, key: K, reason: DisposeReason) => void;
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/**
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* A function that returns the effective calculated size
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* of an entry in the cache.
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*/
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type SizeCalculator<K, V> = (value: V, key: K) => Size;
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/**
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* Options provided to the
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* {@link OptionsBase.fetchMethod} function.
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*/
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interface FetcherOptions<K, V, FC = unknown> {
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signal: AbortSignal;
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options: FetcherFetchOptions<K, V, FC>;
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/**
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* Object provided in the {@link FetchOptions.context} option to
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* {@link LRUCache#fetch}
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*/
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context: FC;
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}
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/**
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* Occasionally, it may be useful to track the internal behavior of the
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* cache, particularly for logging, debugging, or for behavior within the
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* `fetchMethod`. To do this, you can pass a `status` object to the
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* {@link LRUCache#fetch}, {@link LRUCache#get}, {@link LRUCache#set},
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* {@link LRUCache#memo}, and {@link LRUCache#has} methods.
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*
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* The `status` option should be a plain JavaScript object. The following
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* fields will be set on it appropriately, depending on the situation.
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*/
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interface Status<V> {
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/**
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* The status of a set() operation.
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*
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* - add: the item was not found in the cache, and was added
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* - update: the item was in the cache, with the same value provided
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* - replace: the item was in the cache, and replaced
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* - miss: the item was not added to the cache for some reason
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*/
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set?: 'add' | 'update' | 'replace' | 'miss';
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/**
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* the ttl stored for the item, or undefined if ttls are not used.
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*/
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ttl?: Milliseconds;
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/**
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* the start time for the item, or undefined if ttls are not used.
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*/
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start?: Milliseconds;
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/**
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* The timestamp used for TTL calculation
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*/
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now?: Milliseconds;
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/**
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* the remaining ttl for the item, or undefined if ttls are not used.
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*/
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remainingTTL?: Milliseconds;
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/**
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* The calculated size for the item, if sizes are used.
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*/
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entrySize?: Size;
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/**
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* The total calculated size of the cache, if sizes are used.
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*/
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totalCalculatedSize?: Size;
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/**
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* A flag indicating that the item was not stored, due to exceeding the
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* {@link OptionsBase.maxEntrySize}
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*/
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maxEntrySizeExceeded?: true;
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/**
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* The old value, specified in the case of `set:'update'` or
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* `set:'replace'`
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*/
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oldValue?: V;
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/**
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* The results of a {@link LRUCache#has} operation
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*
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* - hit: the item was found in the cache
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* - stale: the item was found in the cache, but is stale
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* - miss: the item was not found in the cache
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*/
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has?: 'hit' | 'stale' | 'miss';
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/**
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* The status of a {@link LRUCache#fetch} operation.
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* Note that this can change as the underlying fetch() moves through
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* various states.
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*
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* - inflight: there is another fetch() for this key which is in process
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* - get: there is no {@link OptionsBase.fetchMethod}, so
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* {@link LRUCache#get} was called.
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* - miss: the item is not in cache, and will be fetched.
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* - hit: the item is in the cache, and was resolved immediately.
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* - stale: the item is in the cache, but stale.
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* - refresh: the item is in the cache, and not stale, but
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* {@link FetchOptions.forceRefresh} was specified.
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*/
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fetch?: 'get' | 'inflight' | 'miss' | 'hit' | 'stale' | 'refresh';
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/**
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* The {@link OptionsBase.fetchMethod} was called
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*/
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fetchDispatched?: true;
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/**
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* The cached value was updated after a successful call to
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* {@link OptionsBase.fetchMethod}
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*/
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fetchUpdated?: true;
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/**
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* The reason for a fetch() rejection. Either the error raised by the
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* {@link OptionsBase.fetchMethod}, or the reason for an
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* AbortSignal.
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*/
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fetchError?: Error;
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/**
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* The fetch received an abort signal
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*/
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fetchAborted?: true;
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/**
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* The abort signal received was ignored, and the fetch was allowed to
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* continue.
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*/
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fetchAbortIgnored?: true;
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/**
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* The fetchMethod promise resolved successfully
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*/
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fetchResolved?: true;
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/**
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* The fetchMethod promise was rejected
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*/
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fetchRejected?: true;
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/**
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* The status of a {@link LRUCache#get} operation.
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*
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* - fetching: The item is currently being fetched. If a previous value
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* is present and allowed, that will be returned.
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* - stale: The item is in the cache, and is stale.
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* - hit: the item is in the cache
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* - miss: the item is not in the cache
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*/
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get?: 'stale' | 'hit' | 'miss';
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/**
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* A fetch or get operation returned a stale value.
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*/
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returnedStale?: true;
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}
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/**
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* options which override the options set in the LRUCache constructor
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* when calling {@link LRUCache#fetch}.
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*
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* This is the union of {@link GetOptions} and {@link SetOptions}, plus
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* {@link OptionsBase.noDeleteOnFetchRejection},
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* {@link OptionsBase.allowStaleOnFetchRejection},
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* {@link FetchOptions.forceRefresh}, and
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* {@link FetcherOptions.context}
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*
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* Any of these may be modified in the {@link OptionsBase.fetchMethod}
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* function, but the {@link GetOptions} fields will of course have no
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* effect, as the {@link LRUCache#get} call already happened by the time
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* the fetchMethod is called.
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*/
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interface FetcherFetchOptions<K, V, FC = unknown> extends Pick<OptionsBase<K, V, FC>, 'allowStale' | 'updateAgeOnGet' | 'noDeleteOnStaleGet' | 'sizeCalculation' | 'ttl' | 'noDisposeOnSet' | 'noUpdateTTL' | 'noDeleteOnFetchRejection' | 'allowStaleOnFetchRejection' | 'ignoreFetchAbort' | 'allowStaleOnFetchAbort'> {
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status?: Status<V>;
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size?: Size;
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}
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/**
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* Options that may be passed to the {@link LRUCache#fetch} method.
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*/
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interface FetchOptions<K, V, FC> extends FetcherFetchOptions<K, V, FC> {
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/**
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* Set to true to force a re-load of the existing data, even if it
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* is not yet stale.
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*/
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forceRefresh?: boolean;
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/**
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* Context provided to the {@link OptionsBase.fetchMethod} as
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* the {@link FetcherOptions.context} param.
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*
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* If the FC type is specified as unknown (the default),
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* undefined or void, then this is optional. Otherwise, it will
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* be required.
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*/
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context?: FC;
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signal?: AbortSignal;
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status?: Status<V>;
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}
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/**
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* Options provided to {@link LRUCache#fetch} when the FC type is something
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* other than `unknown`, `undefined`, or `void`
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*/
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interface FetchOptionsWithContext<K, V, FC> extends FetchOptions<K, V, FC> {
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context: FC;
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}
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/**
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* Options provided to {@link LRUCache#fetch} when the FC type is
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* `undefined` or `void`
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*/
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interface FetchOptionsNoContext<K, V> extends FetchOptions<K, V, undefined> {
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context?: undefined;
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}
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interface MemoOptions<K, V, FC = unknown> extends Pick<OptionsBase<K, V, FC>, 'allowStale' | 'updateAgeOnGet' | 'noDeleteOnStaleGet' | 'sizeCalculation' | 'ttl' | 'noDisposeOnSet' | 'noUpdateTTL' | 'noDeleteOnFetchRejection' | 'allowStaleOnFetchRejection' | 'ignoreFetchAbort' | 'allowStaleOnFetchAbort'> {
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/**
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* Set to true to force a re-load of the existing data, even if it
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* is not yet stale.
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*/
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forceRefresh?: boolean;
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/**
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* Context provided to the {@link OptionsBase.memoMethod} as
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* the {@link MemoizerOptions.context} param.
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*
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* If the FC type is specified as unknown (the default),
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* undefined or void, then this is optional. Otherwise, it will
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* be required.
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*/
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context?: FC;
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status?: Status<V>;
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}
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/**
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* Options provided to {@link LRUCache#memo} when the FC type is something
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* other than `unknown`, `undefined`, or `void`
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*/
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interface MemoOptionsWithContext<K, V, FC> extends MemoOptions<K, V, FC> {
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context: FC;
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}
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/**
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* Options provided to {@link LRUCache#memo} when the FC type is
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* `undefined` or `void`
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*/
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interface MemoOptionsNoContext<K, V> extends MemoOptions<K, V, undefined> {
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context?: undefined;
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}
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/**
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* Options provided to the
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* {@link OptionsBase.memoMethod} function.
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*/
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interface MemoizerOptions<K, V, FC = unknown> {
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options: MemoizerMemoOptions<K, V, FC>;
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/**
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* Object provided in the {@link MemoOptions.context} option to
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* {@link LRUCache#memo}
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*/
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context: FC;
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}
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/**
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* options which override the options set in the LRUCache constructor
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* when calling {@link LRUCache#memo}.
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*
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* This is the union of {@link GetOptions} and {@link SetOptions}, plus
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* {@link MemoOptions.forceRefresh}, and
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* {@link MemoerOptions.context}
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*
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* Any of these may be modified in the {@link OptionsBase.memoMethod}
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* function, but the {@link GetOptions} fields will of course have no
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* effect, as the {@link LRUCache#get} call already happened by the time
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* the memoMethod is called.
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*/
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interface MemoizerMemoOptions<K, V, FC = unknown> extends Pick<OptionsBase<K, V, FC>, 'allowStale' | 'updateAgeOnGet' | 'noDeleteOnStaleGet' | 'sizeCalculation' | 'ttl' | 'noDisposeOnSet' | 'noUpdateTTL'> {
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status?: Status<V>;
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size?: Size;
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start?: Milliseconds;
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}
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/**
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* Options that may be passed to the {@link LRUCache#has} method.
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*/
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interface HasOptions<K, V, FC> extends Pick<OptionsBase<K, V, FC>, 'updateAgeOnHas'> {
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status?: Status<V>;
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}
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/**
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* Options that may be passed to the {@link LRUCache#get} method.
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*/
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interface GetOptions<K, V, FC> extends Pick<OptionsBase<K, V, FC>, 'allowStale' | 'updateAgeOnGet' | 'noDeleteOnStaleGet'> {
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status?: Status<V>;
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}
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/**
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* Options that may be passed to the {@link LRUCache#peek} method.
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*/
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interface PeekOptions<K, V, FC> extends Pick<OptionsBase<K, V, FC>, 'allowStale'> {
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}
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/**
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* Options that may be passed to the {@link LRUCache#set} method.
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*/
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interface SetOptions<K, V, FC> extends Pick<OptionsBase<K, V, FC>, 'sizeCalculation' | 'ttl' | 'noDisposeOnSet' | 'noUpdateTTL'> {
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/**
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* If size tracking is enabled, then setting an explicit size
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* in the {@link LRUCache#set} call will prevent calling the
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* {@link OptionsBase.sizeCalculation} function.
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*/
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size?: Size;
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/**
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* If TTL tracking is enabled, then setting an explicit start
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* time in the {@link LRUCache#set} call will override the
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* default time from `performance.now()` or `Date.now()`.
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*
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* Note that it must be a valid value for whichever time-tracking
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* method is in use.
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*/
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start?: Milliseconds;
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status?: Status<V>;
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}
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/**
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* The type signature for the {@link OptionsBase.fetchMethod} option.
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*/
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type Fetcher<K, V, FC = unknown> = (key: K, staleValue: V | undefined, options: FetcherOptions<K, V, FC>) => Promise<V | undefined | void> | V | undefined | void;
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/**
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* the type signature for the {@link OptionsBase.memoMethod} option.
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*/
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type Memoizer<K, V, FC = unknown> = (key: K, staleValue: V | undefined, options: MemoizerOptions<K, V, FC>) => V;
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/**
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* Options which may be passed to the {@link LRUCache} constructor.
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*
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* Most of these may be overridden in the various options that use
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* them.
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*
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* Despite all being technically optional, the constructor requires that
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* a cache is at minimum limited by one or more of {@link OptionsBase.max},
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* {@link OptionsBase.ttl}, or {@link OptionsBase.maxSize}.
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*
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* If {@link OptionsBase.ttl} is used alone, then it is strongly advised
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* (and in fact required by the type definitions here) that the cache
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* also set {@link OptionsBase.ttlAutopurge}, to prevent potentially
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* unbounded storage.
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*
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* All options are also available on the {@link LRUCache} instance, making
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* it safe to pass an LRUCache instance as the options argumemnt to
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* make another empty cache of the same type.
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*
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* Some options are marked as read-only, because changing them after
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* instantiation is not safe. Changing any of the other options will of
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* course only have an effect on subsequent method calls.
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*/
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interface OptionsBase<K, V, FC> {
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/**
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* The maximum number of items to store in the cache before evicting
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* old entries. This is read-only on the {@link LRUCache} instance,
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* and may not be overridden.
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*
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* If set, then storage space will be pre-allocated at construction
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* time, and the cache will perform significantly faster.
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*
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* Note that significantly fewer items may be stored, if
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* {@link OptionsBase.maxSize} and/or {@link OptionsBase.ttl} are also
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* set.
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*
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* **It is strongly recommended to set a `max` to prevent unbounded growth
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* of the cache.**
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*/
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max?: Count;
|
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/**
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* Max time in milliseconds for items to live in cache before they are
|
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* considered stale. Note that stale items are NOT preemptively removed by
|
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* default, and MAY live in the cache, contributing to its LRU max, long
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* after they have expired, unless {@link OptionsBase.ttlAutopurge} is
|
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* set.
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*
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* If set to `0` (the default value), then that means "do not track
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* TTL", not "expire immediately".
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*
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* Also, as this cache is optimized for LRU/MRU operations, some of
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* the staleness/TTL checks will reduce performance, as they will incur
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* overhead by deleting items.
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*
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* This is not primarily a TTL cache, and does not make strong TTL
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* guarantees. There is no pre-emptive pruning of expired items, but you
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* _may_ set a TTL on the cache, and it will treat expired items as missing
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* when they are fetched, and delete them.
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*
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* Optional, but must be a non-negative integer in ms if specified.
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*
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* This may be overridden by passing an options object to `cache.set()`.
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*
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* At least one of `max`, `maxSize`, or `TTL` is required. This must be a
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* positive integer if set.
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*
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* Even if ttl tracking is enabled, **it is strongly recommended to set a
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* `max` to prevent unbounded growth of the cache.**
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*
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* If ttl tracking is enabled, and `max` and `maxSize` are not set,
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* and `ttlAutopurge` is not set, then a warning will be emitted
|
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* cautioning about the potential for unbounded memory consumption.
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* (The TypeScript definitions will also discourage this.)
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*/
|
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ttl?: Milliseconds;
|
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/**
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|
* Minimum amount of time in ms in which to check for staleness.
|
|
* Defaults to 1, which means that the current time is checked
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* at most once per millisecond.
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*
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* Set to 0 to check the current time every time staleness is tested.
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* (This reduces performance, and is theoretically unnecessary.)
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*
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* Setting this to a higher value will improve performance somewhat
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* while using ttl tracking, albeit at the expense of keeping stale
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* items around a bit longer than their TTLs would indicate.
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*
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* @default 1
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*/
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ttlResolution?: Milliseconds;
|
|
/**
|
|
* Preemptively remove stale items from the cache.
|
|
*
|
|
* Note that this may *significantly* degrade performance, especially if
|
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* the cache is storing a large number of items. It is almost always best
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* to just leave the stale items in the cache, and let them fall out as new
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* items are added.
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*
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|
* Note that this means that {@link OptionsBase.allowStale} is a bit
|
|
* pointless, as stale items will be deleted almost as soon as they
|
|
* expire.
|
|
*
|
|
* Use with caution!
|
|
*/
|
|
ttlAutopurge?: boolean;
|
|
/**
|
|
* When using time-expiring entries with `ttl`, setting this to `true` will
|
|
* make each item's age reset to 0 whenever it is retrieved from cache with
|
|
* {@link LRUCache#get}, causing it to not expire. (It can still fall out
|
|
* of cache based on recency of use, of course.)
|
|
*
|
|
* Has no effect if {@link OptionsBase.ttl} is not set.
|
|
*
|
|
* This may be overridden by passing an options object to `cache.get()`.
|
|
*/
|
|
updateAgeOnGet?: boolean;
|
|
/**
|
|
* When using time-expiring entries with `ttl`, setting this to `true` will
|
|
* make each item's age reset to 0 whenever its presence in the cache is
|
|
* checked with {@link LRUCache#has}, causing it to not expire. (It can
|
|
* still fall out of cache based on recency of use, of course.)
|
|
*
|
|
* Has no effect if {@link OptionsBase.ttl} is not set.
|
|
*/
|
|
updateAgeOnHas?: boolean;
|
|
/**
|
|
* Allow {@link LRUCache#get} and {@link LRUCache#fetch} calls to return
|
|
* stale data, if available.
|
|
*
|
|
* By default, if you set `ttl`, stale items will only be deleted from the
|
|
* cache when you `get(key)`. That is, it's not preemptively pruning items,
|
|
* unless {@link OptionsBase.ttlAutopurge} is set.
|
|
*
|
|
* If you set `allowStale:true`, it'll return the stale value *as well as*
|
|
* deleting it. If you don't set this, then it'll return `undefined` when
|
|
* you try to get a stale entry.
|
|
*
|
|
* Note that when a stale entry is fetched, _even if it is returned due to
|
|
* `allowStale` being set_, it is removed from the cache immediately. You
|
|
* can suppress this behavior by setting
|
|
* {@link OptionsBase.noDeleteOnStaleGet}, either in the constructor, or in
|
|
* the options provided to {@link LRUCache#get}.
|
|
*
|
|
* This may be overridden by passing an options object to `cache.get()`.
|
|
* The `cache.has()` method will always return `false` for stale items.
|
|
*
|
|
* Only relevant if a ttl is set.
|
|
*/
|
|
allowStale?: boolean;
|
|
/**
|
|
* Function that is called on items when they are dropped from the
|
|
* cache, as `dispose(value, key, reason)`.
|
|
*
|
|
* This can be handy if you want to close file descriptors or do
|
|
* other cleanup tasks when items are no longer stored in the cache.
|
|
*
|
|
* **NOTE**: It is called _before_ the item has been fully removed
|
|
* from the cache, so if you want to put it right back in, you need
|
|
* to wait until the next tick. If you try to add it back in during
|
|
* the `dispose()` function call, it will break things in subtle and
|
|
* weird ways.
|
|
*
|
|
* Unlike several other options, this may _not_ be overridden by
|
|
* passing an option to `set()`, for performance reasons.
|
|
*
|
|
* The `reason` will be one of the following strings, corresponding
|
|
* to the reason for the item's deletion:
|
|
*
|
|
* - `evict` Item was evicted to make space for a new addition
|
|
* - `set` Item was overwritten by a new value
|
|
* - `expire` Item expired its TTL
|
|
* - `fetch` Item was deleted due to a failed or aborted fetch, or a
|
|
* fetchMethod returning `undefined.
|
|
* - `delete` Item was removed by explicit `cache.delete(key)`,
|
|
* `cache.clear()`, or `cache.set(key, undefined)`.
|
|
*/
|
|
dispose?: Disposer<K, V>;
|
|
/**
|
|
* The same as {@link OptionsBase.dispose}, but called *after* the entry
|
|
* is completely removed and the cache is once again in a clean state.
|
|
*
|
|
* It is safe to add an item right back into the cache at this point.
|
|
* However, note that it is *very* easy to inadvertently create infinite
|
|
* recursion this way.
|
|
*/
|
|
disposeAfter?: Disposer<K, V>;
|
|
/**
|
|
* Set to true to suppress calling the
|
|
* {@link OptionsBase.dispose} function if the entry key is
|
|
* still accessible within the cache.
|
|
*
|
|
* This may be overridden by passing an options object to
|
|
* {@link LRUCache#set}.
|
|
*
|
|
* Only relevant if `dispose` or `disposeAfter` are set.
|
|
*/
|
|
noDisposeOnSet?: boolean;
|
|
/**
|
|
* Boolean flag to tell the cache to not update the TTL when setting a new
|
|
* value for an existing key (ie, when updating a value rather than
|
|
* inserting a new value). Note that the TTL value is _always_ set (if
|
|
* provided) when adding a new entry into the cache.
|
|
*
|
|
* Has no effect if a {@link OptionsBase.ttl} is not set.
|
|
*
|
|
* May be passed as an option to {@link LRUCache#set}.
|
|
*/
|
|
noUpdateTTL?: boolean;
|
|
/**
|
|
* Set to a positive integer to track the sizes of items added to the
|
|
* cache, and automatically evict items in order to stay below this size.
|
|
* Note that this may result in fewer than `max` items being stored.
|
|
*
|
|
* Attempting to add an item to the cache whose calculated size is greater
|
|
* that this amount will be a no-op. The item will not be cached, and no
|
|
* other items will be evicted.
|
|
*
|
|
* Optional, must be a positive integer if provided.
|
|
*
|
|
* Sets `maxEntrySize` to the same value, unless a different value is
|
|
* provided for `maxEntrySize`.
|
|
*
|
|
* At least one of `max`, `maxSize`, or `TTL` is required. This must be a
|
|
* positive integer if set.
|
|
*
|
|
* Even if size tracking is enabled, **it is strongly recommended to set a
|
|
* `max` to prevent unbounded growth of the cache.**
|
|
*
|
|
* Note also that size tracking can negatively impact performance,
|
|
* though for most cases, only minimally.
|
|
*/
|
|
maxSize?: Size;
|
|
/**
|
|
* The maximum allowed size for any single item in the cache.
|
|
*
|
|
* If a larger item is passed to {@link LRUCache#set} or returned by a
|
|
* {@link OptionsBase.fetchMethod} or {@link OptionsBase.memoMethod}, then
|
|
* it will not be stored in the cache.
|
|
*
|
|
* Attempting to add an item whose calculated size is greater than
|
|
* this amount will not cache the item or evict any old items, but
|
|
* WILL delete an existing value if one is already present.
|
|
*
|
|
* Optional, must be a positive integer if provided. Defaults to
|
|
* the value of `maxSize` if provided.
|
|
*/
|
|
maxEntrySize?: Size;
|
|
/**
|
|
* A function that returns a number indicating the item's size.
|
|
*
|
|
* Requires {@link OptionsBase.maxSize} to be set.
|
|
*
|
|
* If not provided, and {@link OptionsBase.maxSize} or
|
|
* {@link OptionsBase.maxEntrySize} are set, then all
|
|
* {@link LRUCache#set} calls **must** provide an explicit
|
|
* {@link SetOptions.size} or sizeCalculation param.
|
|
*/
|
|
sizeCalculation?: SizeCalculator<K, V>;
|
|
/**
|
|
* Method that provides the implementation for {@link LRUCache#fetch}
|
|
*
|
|
* ```ts
|
|
* fetchMethod(key, staleValue, { signal, options, context })
|
|
* ```
|
|
*
|
|
* If `fetchMethod` is not provided, then `cache.fetch(key)` is equivalent
|
|
* to `Promise.resolve(cache.get(key))`.
|
|
*
|
|
* If at any time, `signal.aborted` is set to `true`, or if the
|
|
* `signal.onabort` method is called, or if it emits an `'abort'` event
|
|
* which you can listen to with `addEventListener`, then that means that
|
|
* the fetch should be abandoned. This may be passed along to async
|
|
* functions aware of AbortController/AbortSignal behavior.
|
|
*
|
|
* The `fetchMethod` should **only** return `undefined` or a Promise
|
|
* resolving to `undefined` if the AbortController signaled an `abort`
|
|
* event. In all other cases, it should return or resolve to a value
|
|
* suitable for adding to the cache.
|
|
*
|
|
* The `options` object is a union of the options that may be provided to
|
|
* `set()` and `get()`. If they are modified, then that will result in
|
|
* modifying the settings to `cache.set()` when the value is resolved, and
|
|
* in the case of
|
|
* {@link OptionsBase.noDeleteOnFetchRejection} and
|
|
* {@link OptionsBase.allowStaleOnFetchRejection}, the handling of
|
|
* `fetchMethod` failures.
|
|
*
|
|
* For example, a DNS cache may update the TTL based on the value returned
|
|
* from a remote DNS server by changing `options.ttl` in the `fetchMethod`.
|
|
*/
|
|
fetchMethod?: Fetcher<K, V, FC>;
|
|
/**
|
|
* Method that provides the implementation for {@link LRUCache#memo}
|
|
*/
|
|
memoMethod?: Memoizer<K, V, FC>;
|
|
/**
|
|
* Set to true to suppress the deletion of stale data when a
|
|
* {@link OptionsBase.fetchMethod} returns a rejected promise.
|
|
*/
|
|
noDeleteOnFetchRejection?: boolean;
|
|
/**
|
|
* Do not delete stale items when they are retrieved with
|
|
* {@link LRUCache#get}.
|
|
*
|
|
* Note that the `get` return value will still be `undefined`
|
|
* unless {@link OptionsBase.allowStale} is true.
|
|
*
|
|
* When using time-expiring entries with `ttl`, by default stale
|
|
* items will be removed from the cache when the key is accessed
|
|
* with `cache.get()`.
|
|
*
|
|
* Setting this option will cause stale items to remain in the cache, until
|
|
* they are explicitly deleted with `cache.delete(key)`, or retrieved with
|
|
* `noDeleteOnStaleGet` set to `false`.
|
|
*
|
|
* This may be overridden by passing an options object to `cache.get()`.
|
|
*
|
|
* Only relevant if a ttl is used.
|
|
*/
|
|
noDeleteOnStaleGet?: boolean;
|
|
/**
|
|
* Set to true to allow returning stale data when a
|
|
* {@link OptionsBase.fetchMethod} throws an error or returns a rejected
|
|
* promise.
|
|
*
|
|
* This differs from using {@link OptionsBase.allowStale} in that stale
|
|
* data will ONLY be returned in the case that the {@link LRUCache#fetch}
|
|
* fails, not any other times.
|
|
*
|
|
* If a `fetchMethod` fails, and there is no stale value available, the
|
|
* `fetch()` will resolve to `undefined`. Ie, all `fetchMethod` errors are
|
|
* suppressed.
|
|
*
|
|
* Implies `noDeleteOnFetchRejection`.
|
|
*
|
|
* This may be set in calls to `fetch()`, or defaulted on the constructor,
|
|
* or overridden by modifying the options object in the `fetchMethod`.
|
|
*/
|
|
allowStaleOnFetchRejection?: boolean;
|
|
/**
|
|
* Set to true to return a stale value from the cache when the
|
|
* `AbortSignal` passed to the {@link OptionsBase.fetchMethod} dispatches
|
|
* an `'abort'` event, whether user-triggered, or due to internal cache
|
|
* behavior.
|
|
*
|
|
* Unless {@link OptionsBase.ignoreFetchAbort} is also set, the underlying
|
|
* {@link OptionsBase.fetchMethod} will still be considered canceled, and
|
|
* any value it returns will be ignored and not cached.
|
|
*
|
|
* Caveat: since fetches are aborted when a new value is explicitly
|
|
* set in the cache, this can lead to fetch returning a stale value,
|
|
* since that was the fallback value _at the moment the `fetch()` was
|
|
* initiated_, even though the new updated value is now present in
|
|
* the cache.
|
|
*
|
|
* For example:
|
|
*
|
|
* ```ts
|
|
* const cache = new LRUCache<string, any>({
|
|
* ttl: 100,
|
|
* fetchMethod: async (url, oldValue, { signal }) => {
|
|
* const res = await fetch(url, { signal })
|
|
* return await res.json()
|
|
* }
|
|
* })
|
|
* cache.set('https://example.com/', { some: 'data' })
|
|
* // 100ms go by...
|
|
* const result = cache.fetch('https://example.com/')
|
|
* cache.set('https://example.com/', { other: 'thing' })
|
|
* console.log(await result) // { some: 'data' }
|
|
* console.log(cache.get('https://example.com/')) // { other: 'thing' }
|
|
* ```
|
|
*/
|
|
allowStaleOnFetchAbort?: boolean;
|
|
/**
|
|
* Set to true to ignore the `abort` event emitted by the `AbortSignal`
|
|
* object passed to {@link OptionsBase.fetchMethod}, and still cache the
|
|
* resulting resolution value, as long as it is not `undefined`.
|
|
*
|
|
* When used on its own, this means aborted {@link LRUCache#fetch} calls
|
|
* are not immediately resolved or rejected when they are aborted, and
|
|
* instead take the full time to await.
|
|
*
|
|
* When used with {@link OptionsBase.allowStaleOnFetchAbort}, aborted
|
|
* {@link LRUCache#fetch} calls will resolve immediately to their stale
|
|
* cached value or `undefined`, and will continue to process and eventually
|
|
* update the cache when they resolve, as long as the resulting value is
|
|
* not `undefined`, thus supporting a "return stale on timeout while
|
|
* refreshing" mechanism by passing `AbortSignal.timeout(n)` as the signal.
|
|
*
|
|
* For example:
|
|
*
|
|
* ```ts
|
|
* const c = new LRUCache({
|
|
* ttl: 100,
|
|
* ignoreFetchAbort: true,
|
|
* allowStaleOnFetchAbort: true,
|
|
* fetchMethod: async (key, oldValue, { signal }) => {
|
|
* // note: do NOT pass the signal to fetch()!
|
|
* // let's say this fetch can take a long time.
|
|
* const res = await fetch(`https://slow-backend-server/${key}`)
|
|
* return await res.json()
|
|
* },
|
|
* })
|
|
*
|
|
* // this will return the stale value after 100ms, while still
|
|
* // updating in the background for next time.
|
|
* const val = await c.fetch('key', { signal: AbortSignal.timeout(100) })
|
|
* ```
|
|
*
|
|
* **Note**: regardless of this setting, an `abort` event _is still
|
|
* emitted on the `AbortSignal` object_, so may result in invalid results
|
|
* when passed to other underlying APIs that use AbortSignals.
|
|
*
|
|
* This may be overridden in the {@link OptionsBase.fetchMethod} or the
|
|
* call to {@link LRUCache#fetch}.
|
|
*/
|
|
ignoreFetchAbort?: boolean;
|
|
}
|
|
interface OptionsMaxLimit<K, V, FC> extends OptionsBase<K, V, FC> {
|
|
max: Count;
|
|
}
|
|
interface OptionsTTLLimit<K, V, FC> extends OptionsBase<K, V, FC> {
|
|
ttl: Milliseconds;
|
|
ttlAutopurge: boolean;
|
|
}
|
|
interface OptionsSizeLimit<K, V, FC> extends OptionsBase<K, V, FC> {
|
|
maxSize: Size;
|
|
}
|
|
/**
|
|
* The valid safe options for the {@link LRUCache} constructor
|
|
*/
|
|
type Options<K, V, FC> = OptionsMaxLimit<K, V, FC> | OptionsSizeLimit<K, V, FC> | OptionsTTLLimit<K, V, FC>;
|
|
/**
|
|
* Entry objects used by {@link LRUCache#load} and {@link LRUCache#dump},
|
|
* and returned by {@link LRUCache#info}.
|
|
*/
|
|
interface Entry<V> {
|
|
value: V;
|
|
ttl?: Milliseconds;
|
|
size?: Size;
|
|
start?: Milliseconds;
|
|
}
|
|
}
|
|
/**
|
|
* Default export, the thing you're using this module to get.
|
|
*
|
|
* The `K` and `V` types define the key and value types, respectively. The
|
|
* optional `FC` type defines the type of the `context` object passed to
|
|
* `cache.fetch()` and `cache.memo()`.
|
|
*
|
|
* Keys and values **must not** be `null` or `undefined`.
|
|
*
|
|
* All properties from the options object (with the exception of `max`,
|
|
* `maxSize`, `fetchMethod`, `memoMethod`, `dispose` and `disposeAfter`) are
|
|
* added as normal public members. (The listed options are read-only getters.)
|
|
*
|
|
* Changing any of these will alter the defaults for subsequent method calls.
|
|
*/
|
|
export declare class LRUCache<K extends {}, V extends {}, FC = unknown> implements Map<K, V> {
|
|
#private;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.ttl}
|
|
*/
|
|
ttl: LRUCache.Milliseconds;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.ttlResolution}
|
|
*/
|
|
ttlResolution: LRUCache.Milliseconds;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.ttlAutopurge}
|
|
*/
|
|
ttlAutopurge: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.updateAgeOnGet}
|
|
*/
|
|
updateAgeOnGet: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.updateAgeOnHas}
|
|
*/
|
|
updateAgeOnHas: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.allowStale}
|
|
*/
|
|
allowStale: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.noDisposeOnSet}
|
|
*/
|
|
noDisposeOnSet: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.noUpdateTTL}
|
|
*/
|
|
noUpdateTTL: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.maxEntrySize}
|
|
*/
|
|
maxEntrySize: LRUCache.Size;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.sizeCalculation}
|
|
*/
|
|
sizeCalculation?: LRUCache.SizeCalculator<K, V>;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.noDeleteOnFetchRejection}
|
|
*/
|
|
noDeleteOnFetchRejection: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.noDeleteOnStaleGet}
|
|
*/
|
|
noDeleteOnStaleGet: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.allowStaleOnFetchAbort}
|
|
*/
|
|
allowStaleOnFetchAbort: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.allowStaleOnFetchRejection}
|
|
*/
|
|
allowStaleOnFetchRejection: boolean;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.ignoreFetchAbort}
|
|
*/
|
|
ignoreFetchAbort: boolean;
|
|
/**
|
|
* Do not call this method unless you need to inspect the
|
|
* inner workings of the cache. If anything returned by this
|
|
* object is modified in any way, strange breakage may occur.
|
|
*
|
|
* These fields are private for a reason!
|
|
*
|
|
* @internal
|
|
*/
|
|
static unsafeExposeInternals<K extends {}, V extends {}, FC extends unknown = unknown>(c: LRUCache<K, V, FC>): {
|
|
starts: ZeroArray | undefined;
|
|
ttls: ZeroArray | undefined;
|
|
sizes: ZeroArray | undefined;
|
|
keyMap: Map<K, number>;
|
|
keyList: (K | undefined)[];
|
|
valList: (V | BackgroundFetch<V> | undefined)[];
|
|
next: NumberArray;
|
|
prev: NumberArray;
|
|
readonly head: Index;
|
|
readonly tail: Index;
|
|
free: StackLike;
|
|
isBackgroundFetch: (p: any) => boolean;
|
|
backgroundFetch: (k: K, index: number | undefined, options: LRUCache.FetchOptions<K, V, FC>, context: any) => BackgroundFetch<V>;
|
|
moveToTail: (index: number) => void;
|
|
indexes: (options?: {
|
|
allowStale: boolean;
|
|
}) => Generator<Index, void, unknown>;
|
|
rindexes: (options?: {
|
|
allowStale: boolean;
|
|
}) => Generator<Index, void, unknown>;
|
|
isStale: (index: number | undefined) => boolean;
|
|
};
|
|
/**
|
|
* {@link LRUCache.OptionsBase.max} (read-only)
|
|
*/
|
|
get max(): LRUCache.Count;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.maxSize} (read-only)
|
|
*/
|
|
get maxSize(): LRUCache.Count;
|
|
/**
|
|
* The total computed size of items in the cache (read-only)
|
|
*/
|
|
get calculatedSize(): LRUCache.Size;
|
|
/**
|
|
* The number of items stored in the cache (read-only)
|
|
*/
|
|
get size(): LRUCache.Count;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.fetchMethod} (read-only)
|
|
*/
|
|
get fetchMethod(): LRUCache.Fetcher<K, V, FC> | undefined;
|
|
get memoMethod(): LRUCache.Memoizer<K, V, FC> | undefined;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.dispose} (read-only)
|
|
*/
|
|
get dispose(): LRUCache.Disposer<K, V> | undefined;
|
|
/**
|
|
* {@link LRUCache.OptionsBase.disposeAfter} (read-only)
|
|
*/
|
|
get disposeAfter(): LRUCache.Disposer<K, V> | undefined;
|
|
constructor(options: LRUCache.Options<K, V, FC> | LRUCache<K, V, FC>);
|
|
/**
|
|
* Return the number of ms left in the item's TTL. If item is not in cache,
|
|
* returns `0`. Returns `Infinity` if item is in cache without a defined TTL.
|
|
*/
|
|
getRemainingTTL(key: K): number;
|
|
/**
|
|
* Return a generator yielding `[key, value]` pairs,
|
|
* in order from most recently used to least recently used.
|
|
*/
|
|
entries(): Generator<[K, V], void, unknown>;
|
|
/**
|
|
* Inverse order version of {@link LRUCache.entries}
|
|
*
|
|
* Return a generator yielding `[key, value]` pairs,
|
|
* in order from least recently used to most recently used.
|
|
*/
|
|
rentries(): Generator<(K | V | BackgroundFetch<V> | undefined)[], void, unknown>;
|
|
/**
|
|
* Return a generator yielding the keys in the cache,
|
|
* in order from most recently used to least recently used.
|
|
*/
|
|
keys(): Generator<K, void, unknown>;
|
|
/**
|
|
* Inverse order version of {@link LRUCache.keys}
|
|
*
|
|
* Return a generator yielding the keys in the cache,
|
|
* in order from least recently used to most recently used.
|
|
*/
|
|
rkeys(): Generator<K, void, unknown>;
|
|
/**
|
|
* Return a generator yielding the values in the cache,
|
|
* in order from most recently used to least recently used.
|
|
*/
|
|
values(): Generator<V, void, unknown>;
|
|
/**
|
|
* Inverse order version of {@link LRUCache.values}
|
|
*
|
|
* Return a generator yielding the values in the cache,
|
|
* in order from least recently used to most recently used.
|
|
*/
|
|
rvalues(): Generator<V | BackgroundFetch<V> | undefined, void, unknown>;
|
|
/**
|
|
* Iterating over the cache itself yields the same results as
|
|
* {@link LRUCache.entries}
|
|
*/
|
|
[Symbol.iterator](): Generator<[K, V], void, unknown>;
|
|
/**
|
|
* A String value that is used in the creation of the default string
|
|
* description of an object. Called by the built-in method
|
|
* `Object.prototype.toString`.
|
|
*/
|
|
[Symbol.toStringTag]: string;
|
|
/**
|
|
* Find a value for which the supplied fn method returns a truthy value,
|
|
* similar to `Array.find()`. fn is called as `fn(value, key, cache)`.
|
|
*/
|
|
find(fn: (v: V, k: K, self: LRUCache<K, V, FC>) => boolean, getOptions?: LRUCache.GetOptions<K, V, FC>): V | undefined;
|
|
/**
|
|
* Call the supplied function on each item in the cache, in order from most
|
|
* recently used to least recently used.
|
|
*
|
|
* `fn` is called as `fn(value, key, cache)`.
|
|
*
|
|
* If `thisp` is provided, function will be called in the `this`-context of
|
|
* the provided object, or the cache if no `thisp` object is provided.
|
|
*
|
|
* Does not update age or recenty of use, or iterate over stale values.
|
|
*/
|
|
forEach(fn: (v: V, k: K, self: LRUCache<K, V, FC>) => any, thisp?: any): void;
|
|
/**
|
|
* The same as {@link LRUCache.forEach} but items are iterated over in
|
|
* reverse order. (ie, less recently used items are iterated over first.)
|
|
*/
|
|
rforEach(fn: (v: V, k: K, self: LRUCache<K, V, FC>) => any, thisp?: any): void;
|
|
/**
|
|
* Delete any stale entries. Returns true if anything was removed,
|
|
* false otherwise.
|
|
*/
|
|
purgeStale(): boolean;
|
|
/**
|
|
* Get the extended info about a given entry, to get its value, size, and
|
|
* TTL info simultaneously. Returns `undefined` if the key is not present.
|
|
*
|
|
* Unlike {@link LRUCache#dump}, which is designed to be portable and survive
|
|
* serialization, the `start` value is always the current timestamp, and the
|
|
* `ttl` is a calculated remaining time to live (negative if expired).
|
|
*
|
|
* Always returns stale values, if their info is found in the cache, so be
|
|
* sure to check for expirations (ie, a negative {@link LRUCache.Entry#ttl})
|
|
* if relevant.
|
|
*/
|
|
info(key: K): LRUCache.Entry<V> | undefined;
|
|
/**
|
|
* Return an array of [key, {@link LRUCache.Entry}] tuples which can be
|
|
* passed to {@link LRLUCache#load}.
|
|
*
|
|
* The `start` fields are calculated relative to a portable `Date.now()`
|
|
* timestamp, even if `performance.now()` is available.
|
|
*
|
|
* Stale entries are always included in the `dump`, even if
|
|
* {@link LRUCache.OptionsBase.allowStale} is false.
|
|
*
|
|
* Note: this returns an actual array, not a generator, so it can be more
|
|
* easily passed around.
|
|
*/
|
|
dump(): [K, LRUCache.Entry<V>][];
|
|
/**
|
|
* Reset the cache and load in the items in entries in the order listed.
|
|
*
|
|
* The shape of the resulting cache may be different if the same options are
|
|
* not used in both caches.
|
|
*
|
|
* The `start` fields are assumed to be calculated relative to a portable
|
|
* `Date.now()` timestamp, even if `performance.now()` is available.
|
|
*/
|
|
load(arr: [K, LRUCache.Entry<V>][]): void;
|
|
/**
|
|
* Add a value to the cache.
|
|
*
|
|
* Note: if `undefined` is specified as a value, this is an alias for
|
|
* {@link LRUCache#delete}
|
|
*
|
|
* Fields on the {@link LRUCache.SetOptions} options param will override
|
|
* their corresponding values in the constructor options for the scope
|
|
* of this single `set()` operation.
|
|
*
|
|
* If `start` is provided, then that will set the effective start
|
|
* time for the TTL calculation. Note that this must be a previous
|
|
* value of `performance.now()` if supported, or a previous value of
|
|
* `Date.now()` if not.
|
|
*
|
|
* Options object may also include `size`, which will prevent
|
|
* calling the `sizeCalculation` function and just use the specified
|
|
* number if it is a positive integer, and `noDisposeOnSet` which
|
|
* will prevent calling a `dispose` function in the case of
|
|
* overwrites.
|
|
*
|
|
* If the `size` (or return value of `sizeCalculation`) for a given
|
|
* entry is greater than `maxEntrySize`, then the item will not be
|
|
* added to the cache.
|
|
*
|
|
* Will update the recency of the entry.
|
|
*
|
|
* If the value is `undefined`, then this is an alias for
|
|
* `cache.delete(key)`. `undefined` is never stored in the cache.
|
|
*/
|
|
set(k: K, v: V | BackgroundFetch<V> | undefined, setOptions?: LRUCache.SetOptions<K, V, FC>): this;
|
|
/**
|
|
* Evict the least recently used item, returning its value or
|
|
* `undefined` if cache is empty.
|
|
*/
|
|
pop(): V | undefined;
|
|
/**
|
|
* Check if a key is in the cache, without updating the recency of use.
|
|
* Will return false if the item is stale, even though it is technically
|
|
* in the cache.
|
|
*
|
|
* Check if a key is in the cache, without updating the recency of
|
|
* use. Age is updated if {@link LRUCache.OptionsBase.updateAgeOnHas} is set
|
|
* to `true` in either the options or the constructor.
|
|
*
|
|
* Will return `false` if the item is stale, even though it is technically in
|
|
* the cache. The difference can be determined (if it matters) by using a
|
|
* `status` argument, and inspecting the `has` field.
|
|
*
|
|
* Will not update item age unless
|
|
* {@link LRUCache.OptionsBase.updateAgeOnHas} is set.
|
|
*/
|
|
has(k: K, hasOptions?: LRUCache.HasOptions<K, V, FC>): boolean;
|
|
/**
|
|
* Like {@link LRUCache#get} but doesn't update recency or delete stale
|
|
* items.
|
|
*
|
|
* Returns `undefined` if the item is stale, unless
|
|
* {@link LRUCache.OptionsBase.allowStale} is set.
|
|
*/
|
|
peek(k: K, peekOptions?: LRUCache.PeekOptions<K, V, FC>): V | undefined;
|
|
/**
|
|
* Make an asynchronous cached fetch using the
|
|
* {@link LRUCache.OptionsBase.fetchMethod} function.
|
|
*
|
|
* If the value is in the cache and not stale, then the returned
|
|
* Promise resolves to the value.
|
|
*
|
|
* If not in the cache, or beyond its TTL staleness, then
|
|
* `fetchMethod(key, staleValue, { options, signal, context })` is
|
|
* called, and the value returned will be added to the cache once
|
|
* resolved.
|
|
*
|
|
* If called with `allowStale`, and an asynchronous fetch is
|
|
* currently in progress to reload a stale value, then the former
|
|
* stale value will be returned.
|
|
*
|
|
* If called with `forceRefresh`, then the cached item will be
|
|
* re-fetched, even if it is not stale. However, if `allowStale` is also
|
|
* set, then the old value will still be returned. This is useful
|
|
* in cases where you want to force a reload of a cached value. If
|
|
* a background fetch is already in progress, then `forceRefresh`
|
|
* has no effect.
|
|
*
|
|
* If multiple fetches for the same key are issued, then they will all be
|
|
* coalesced into a single call to fetchMethod.
|
|
*
|
|
* Note that this means that handling options such as
|
|
* {@link LRUCache.OptionsBase.allowStaleOnFetchAbort},
|
|
* {@link LRUCache.FetchOptions.signal},
|
|
* and {@link LRUCache.OptionsBase.allowStaleOnFetchRejection} will be
|
|
* determined by the FIRST fetch() call for a given key.
|
|
*
|
|
* This is a known (fixable) shortcoming which will be addresed on when
|
|
* someone complains about it, as the fix would involve added complexity and
|
|
* may not be worth the costs for this edge case.
|
|
*
|
|
* If {@link LRUCache.OptionsBase.fetchMethod} is not specified, then this is
|
|
* effectively an alias for `Promise.resolve(cache.get(key))`.
|
|
*
|
|
* When the fetch method resolves to a value, if the fetch has not
|
|
* been aborted due to deletion, eviction, or being overwritten,
|
|
* then it is added to the cache using the options provided.
|
|
*
|
|
* If the key is evicted or deleted before the `fetchMethod`
|
|
* resolves, then the AbortSignal passed to the `fetchMethod` will
|
|
* receive an `abort` event, and the promise returned by `fetch()`
|
|
* will reject with the reason for the abort.
|
|
*
|
|
* If a `signal` is passed to the `fetch()` call, then aborting the
|
|
* signal will abort the fetch and cause the `fetch()` promise to
|
|
* reject with the reason provided.
|
|
*
|
|
* **Setting `context`**
|
|
*
|
|
* If an `FC` type is set to a type other than `unknown`, `void`, or
|
|
* `undefined` in the {@link LRUCache} constructor, then all
|
|
* calls to `cache.fetch()` _must_ provide a `context` option. If
|
|
* set to `undefined` or `void`, then calls to fetch _must not_
|
|
* provide a `context` option.
|
|
*
|
|
* The `context` param allows you to provide arbitrary data that
|
|
* might be relevant in the course of fetching the data. It is only
|
|
* relevant for the course of a single `fetch()` operation, and
|
|
* discarded afterwards.
|
|
*
|
|
* **Note: `fetch()` calls are inflight-unique**
|
|
*
|
|
* If you call `fetch()` multiple times with the same key value,
|
|
* then every call after the first will resolve on the same
|
|
* promise<sup>1</sup>,
|
|
* _even if they have different settings that would otherwise change
|
|
* the behavior of the fetch_, such as `noDeleteOnFetchRejection`
|
|
* or `ignoreFetchAbort`.
|
|
*
|
|
* In most cases, this is not a problem (in fact, only fetching
|
|
* something once is what you probably want, if you're caching in
|
|
* the first place). If you are changing the fetch() options
|
|
* dramatically between runs, there's a good chance that you might
|
|
* be trying to fit divergent semantics into a single object, and
|
|
* would be better off with multiple cache instances.
|
|
*
|
|
* **1**: Ie, they're not the "same Promise", but they resolve at
|
|
* the same time, because they're both waiting on the same
|
|
* underlying fetchMethod response.
|
|
*/
|
|
fetch(k: K, fetchOptions: unknown extends FC ? LRUCache.FetchOptions<K, V, FC> : FC extends undefined | void ? LRUCache.FetchOptionsNoContext<K, V> : LRUCache.FetchOptionsWithContext<K, V, FC>): Promise<undefined | V>;
|
|
fetch(k: unknown extends FC ? K : FC extends undefined | void ? K : never, fetchOptions?: unknown extends FC ? LRUCache.FetchOptions<K, V, FC> : FC extends undefined | void ? LRUCache.FetchOptionsNoContext<K, V> : never): Promise<undefined | V>;
|
|
/**
|
|
* In some cases, `cache.fetch()` may resolve to `undefined`, either because
|
|
* a {@link LRUCache.OptionsBase#fetchMethod} was not provided (turning
|
|
* `cache.fetch(k)` into just an async wrapper around `cache.get(k)`) or
|
|
* because `ignoreFetchAbort` was specified (either to the constructor or
|
|
* in the {@link LRUCache.FetchOptions}). Also, the
|
|
* {@link OptionsBase.fetchMethod} may return `undefined` or `void`, making
|
|
* the test even more complicated.
|
|
*
|
|
* Because inferring the cases where `undefined` might be returned are so
|
|
* cumbersome, but testing for `undefined` can also be annoying, this method
|
|
* can be used, which will reject if `this.fetch()` resolves to undefined.
|
|
*/
|
|
forceFetch(k: K, fetchOptions: unknown extends FC ? LRUCache.FetchOptions<K, V, FC> : FC extends undefined | void ? LRUCache.FetchOptionsNoContext<K, V> : LRUCache.FetchOptionsWithContext<K, V, FC>): Promise<V>;
|
|
forceFetch(k: unknown extends FC ? K : FC extends undefined | void ? K : never, fetchOptions?: unknown extends FC ? LRUCache.FetchOptions<K, V, FC> : FC extends undefined | void ? LRUCache.FetchOptionsNoContext<K, V> : never): Promise<V>;
|
|
/**
|
|
* If the key is found in the cache, then this is equivalent to
|
|
* {@link LRUCache#get}. If not, in the cache, then calculate the value using
|
|
* the {@link LRUCache.OptionsBase.memoMethod}, and add it to the cache.
|
|
*
|
|
* If an `FC` type is set to a type other than `unknown`, `void`, or
|
|
* `undefined` in the LRUCache constructor, then all calls to `cache.memo()`
|
|
* _must_ provide a `context` option. If set to `undefined` or `void`, then
|
|
* calls to memo _must not_ provide a `context` option.
|
|
*
|
|
* The `context` param allows you to provide arbitrary data that might be
|
|
* relevant in the course of fetching the data. It is only relevant for the
|
|
* course of a single `memo()` operation, and discarded afterwards.
|
|
*/
|
|
memo(k: K, memoOptions: unknown extends FC ? LRUCache.MemoOptions<K, V, FC> : FC extends undefined | void ? LRUCache.MemoOptionsNoContext<K, V> : LRUCache.MemoOptionsWithContext<K, V, FC>): V;
|
|
memo(k: unknown extends FC ? K : FC extends undefined | void ? K : never, memoOptions?: unknown extends FC ? LRUCache.MemoOptions<K, V, FC> : FC extends undefined | void ? LRUCache.MemoOptionsNoContext<K, V> : never): V;
|
|
/**
|
|
* Return a value from the cache. Will update the recency of the cache
|
|
* entry found.
|
|
*
|
|
* If the key is not found, get() will return `undefined`.
|
|
*/
|
|
get(k: K, getOptions?: LRUCache.GetOptions<K, V, FC>): V | undefined;
|
|
/**
|
|
* Deletes a key out of the cache.
|
|
*
|
|
* Returns true if the key was deleted, false otherwise.
|
|
*/
|
|
delete(k: K): boolean;
|
|
/**
|
|
* Clear the cache entirely, throwing away all values.
|
|
*/
|
|
clear(): void;
|
|
}
|
|
//# sourceMappingURL=index.d.ts.map
|