index.js 50 KB

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394959697989910010110210310410510610710810911011111211311411511611711811912012112212312412512612712812913013113213313413513613713813914014114214314414514614714814915015115215315415515615715815916016116216316416516616716816917017117217317417517617717817918018118218318418518618718818919019119219319419519619719819920020120220320420520620720820921021121221321421521621721821922022122222322422522622722822923023123223323423523623723823924024124224324424524624724824925025125225325425525625725825926026126226326426526626726826927027127227327427527627727827928028128228328428528628728828929029129229329429529629729829930030130230330430530630730830931031131231331431531631731831932032132232332432532632732832933033133233333433533633733833934034134234334434534634734834935035135235335435535635735835936036136236336436536636736836937037137237337437537637737837938038138238338438538638738838939039139239339439539639739839940040140240340440540640740840941041141241341441541641741841942042142242342442542642742842943043143243343443543643743843944044144244344444544644744844945045145245345445545645745845946046146246346446546646746846947047147247347447547647747847948048148248348448548648748848949049149249349449549649749849950050150250350450550650750850951051151251351451551651751851952052152252352452552652752852953053153253353453553653753853954054154254354454554654754854955055155255355455555655755855956056156256356456556656756856957057157257357457557657757857958058158258358458558658758858959059159259359459559659759859960060160260360460560660760860961061161261361461561661761861962062162262362462562662762862963063163263363463563663763863964064164264364464564664764864965065165265365465565665765865966066166266366466566666766866967067167267367467567667767867968068168268368468568668768868969069169269369469569669769869970070170270370470570670770870971071171271371471571671771871972072172272372472572672772872973073173273373473573673773873974074174274374474574674774874975075175275375475575675775875976076176276376476576676776876977077177277377477577677777877978078178278378478578678778878979079179279379479579679779879980080180280380480580680780880981081181281381481581681781881982082182282382482582682782882983083183283383483583683783883984084184284384484584684784884985085185285385485585685785885986086186286386486586686786886987087187287387487587687787887988088188288388488588688788888989089189289389489589689789889990090190290390490590690790890991091191291391491591691791891992092192292392492592692792892993093193293393493593693793893994094194294394494594694794894995095195295395495595695795895996096196296396496596696796896997097197297397497597697797897998098198298398498598698798898999099199299399499599699799899910001001100210031004100510061007100810091010101110121013101410151016101710181019102010211022102310241025102610271028102910301031103210331034103510361037103810391040104110421043104410451046104710481049105010511052105310541055105610571058105910601061106210631064106510661067106810691070107110721073107410751076107710781079108010811082108310841085108610871088108910901091109210931094109510961097109810991100110111021103110411051106110711081109111011111112111311141115111611171118111911201121112211231124112511261127112811291130113111321133113411351136113711381139114011411142114311441145114611471148114911501151115211531154115511561157115811591160116111621163116411651166116711681169117011711172117311741175117611771178117911801181118211831184118511861187118811891190119111921193119411951196119711981199120012011202120312041205120612071208120912101211121212131214121512161217121812191220122112221223122412251226122712281229123012311232123312341235123612371238123912401241124212431244124512461247124812491250125112521253125412551256125712581259126012611262126312641265126612671268126912701271127212731274127512761277127812791280128112821283128412851286128712881289129012911292129312941295129612971298129913001301130213031304130513061307130813091310131113121313131413151316131713181319132013211322132313241325132613271328132913301331133213331334133513361337133813391340134113421343134413451346134713481349135013511352135313541355135613571358135913601361136213631364136513661367136813691370137113721373137413751376137713781379138013811382138313841385138613871388138913901391139213931394139513961397139813991400140114021403140414051406140714081409141014111412141314141415141614171418141914201421142214231424142514261427142814291430143114321433143414351436143714381439144014411442
  1. /**
  2. * @module LRUCache
  3. */
  4. const perf = typeof performance === 'object' &&
  5. performance &&
  6. typeof performance.now === 'function'
  7. ? performance
  8. : Date;
  9. const warned = new Set();
  10. /* c8 ignore start */
  11. const PROCESS = (typeof process === 'object' && !!process ? process : {});
  12. /* c8 ignore start */
  13. const emitWarning = (msg, type, code, fn) => {
  14. typeof PROCESS.emitWarning === 'function'
  15. ? PROCESS.emitWarning(msg, type, code, fn)
  16. : console.error(`[${code}] ${type}: ${msg}`);
  17. };
  18. let AC = globalThis.AbortController;
  19. let AS = globalThis.AbortSignal;
  20. /* c8 ignore start */
  21. if (typeof AC === 'undefined') {
  22. //@ts-ignore
  23. AS = class AbortSignal {
  24. onabort;
  25. _onabort = [];
  26. reason;
  27. aborted = false;
  28. addEventListener(_, fn) {
  29. this._onabort.push(fn);
  30. }
  31. };
  32. //@ts-ignore
  33. AC = class AbortController {
  34. constructor() {
  35. warnACPolyfill();
  36. }
  37. signal = new AS();
  38. abort(reason) {
  39. if (this.signal.aborted)
  40. return;
  41. //@ts-ignore
  42. this.signal.reason = reason;
  43. //@ts-ignore
  44. this.signal.aborted = true;
  45. //@ts-ignore
  46. for (const fn of this.signal._onabort) {
  47. fn(reason);
  48. }
  49. this.signal.onabort?.(reason);
  50. }
  51. };
  52. let printACPolyfillWarning = PROCESS.env?.LRU_CACHE_IGNORE_AC_WARNING !== '1';
  53. const warnACPolyfill = () => {
  54. if (!printACPolyfillWarning)
  55. return;
  56. printACPolyfillWarning = false;
  57. emitWarning('AbortController is not defined. If using lru-cache in ' +
  58. 'node 14, load an AbortController polyfill from the ' +
  59. '`node-abort-controller` package. A minimal polyfill is ' +
  60. 'provided for use by LRUCache.fetch(), but it should not be ' +
  61. 'relied upon in other contexts (eg, passing it to other APIs that ' +
  62. 'use AbortController/AbortSignal might have undesirable effects). ' +
  63. 'You may disable this with LRU_CACHE_IGNORE_AC_WARNING=1 in the env.', 'NO_ABORT_CONTROLLER', 'ENOTSUP', warnACPolyfill);
  64. };
  65. }
  66. /* c8 ignore stop */
  67. const shouldWarn = (code) => !warned.has(code);
  68. const TYPE = Symbol('type');
  69. const isPosInt = (n) => n && n === Math.floor(n) && n > 0 && isFinite(n);
  70. /* c8 ignore start */
  71. // This is a little bit ridiculous, tbh.
  72. // The maximum array length is 2^32-1 or thereabouts on most JS impls.
  73. // And well before that point, you're caching the entire world, I mean,
  74. // that's ~32GB of just integers for the next/prev links, plus whatever
  75. // else to hold that many keys and values. Just filling the memory with
  76. // zeroes at init time is brutal when you get that big.
  77. // But why not be complete?
  78. // Maybe in the future, these limits will have expanded.
  79. const getUintArray = (max) => !isPosInt(max)
  80. ? null
  81. : max <= Math.pow(2, 8)
  82. ? Uint8Array
  83. : max <= Math.pow(2, 16)
  84. ? Uint16Array
  85. : max <= Math.pow(2, 32)
  86. ? Uint32Array
  87. : max <= Number.MAX_SAFE_INTEGER
  88. ? ZeroArray
  89. : null;
  90. /* c8 ignore stop */
  91. class ZeroArray extends Array {
  92. constructor(size) {
  93. super(size);
  94. this.fill(0);
  95. }
  96. }
  97. class Stack {
  98. heap;
  99. length;
  100. // private constructor
  101. static #constructing = false;
  102. static create(max) {
  103. const HeapCls = getUintArray(max);
  104. if (!HeapCls)
  105. return [];
  106. Stack.#constructing = true;
  107. const s = new Stack(max, HeapCls);
  108. Stack.#constructing = false;
  109. return s;
  110. }
  111. constructor(max, HeapCls) {
  112. /* c8 ignore start */
  113. if (!Stack.#constructing) {
  114. throw new TypeError('instantiate Stack using Stack.create(n)');
  115. }
  116. /* c8 ignore stop */
  117. this.heap = new HeapCls(max);
  118. this.length = 0;
  119. }
  120. push(n) {
  121. this.heap[this.length++] = n;
  122. }
  123. pop() {
  124. return this.heap[--this.length];
  125. }
  126. }
  127. /**
  128. * Default export, the thing you're using this module to get.
  129. *
  130. * All properties from the options object (with the exception of
  131. * {@link OptionsBase.max} and {@link OptionsBase.maxSize}) are added as
  132. * normal public members. (`max` and `maxBase` are read-only getters.)
  133. * Changing any of these will alter the defaults for subsequent method calls,
  134. * but is otherwise safe.
  135. */
  136. export class LRUCache {
  137. // properties coming in from the options of these, only max and maxSize
  138. // really *need* to be protected. The rest can be modified, as they just
  139. // set defaults for various methods.
  140. #max;
  141. #maxSize;
  142. #dispose;
  143. #disposeAfter;
  144. #fetchMethod;
  145. /**
  146. * {@link LRUCache.OptionsBase.ttl}
  147. */
  148. ttl;
  149. /**
  150. * {@link LRUCache.OptionsBase.ttlResolution}
  151. */
  152. ttlResolution;
  153. /**
  154. * {@link LRUCache.OptionsBase.ttlAutopurge}
  155. */
  156. ttlAutopurge;
  157. /**
  158. * {@link LRUCache.OptionsBase.updateAgeOnGet}
  159. */
  160. updateAgeOnGet;
  161. /**
  162. * {@link LRUCache.OptionsBase.updateAgeOnHas}
  163. */
  164. updateAgeOnHas;
  165. /**
  166. * {@link LRUCache.OptionsBase.allowStale}
  167. */
  168. allowStale;
  169. /**
  170. * {@link LRUCache.OptionsBase.noDisposeOnSet}
  171. */
  172. noDisposeOnSet;
  173. /**
  174. * {@link LRUCache.OptionsBase.noUpdateTTL}
  175. */
  176. noUpdateTTL;
  177. /**
  178. * {@link LRUCache.OptionsBase.maxEntrySize}
  179. */
  180. maxEntrySize;
  181. /**
  182. * {@link LRUCache.OptionsBase.sizeCalculation}
  183. */
  184. sizeCalculation;
  185. /**
  186. * {@link LRUCache.OptionsBase.noDeleteOnFetchRejection}
  187. */
  188. noDeleteOnFetchRejection;
  189. /**
  190. * {@link LRUCache.OptionsBase.noDeleteOnStaleGet}
  191. */
  192. noDeleteOnStaleGet;
  193. /**
  194. * {@link LRUCache.OptionsBase.allowStaleOnFetchAbort}
  195. */
  196. allowStaleOnFetchAbort;
  197. /**
  198. * {@link LRUCache.OptionsBase.allowStaleOnFetchRejection}
  199. */
  200. allowStaleOnFetchRejection;
  201. /**
  202. * {@link LRUCache.OptionsBase.ignoreFetchAbort}
  203. */
  204. ignoreFetchAbort;
  205. // computed properties
  206. #size;
  207. #calculatedSize;
  208. #keyMap;
  209. #keyList;
  210. #valList;
  211. #next;
  212. #prev;
  213. #head;
  214. #tail;
  215. #free;
  216. #disposed;
  217. #sizes;
  218. #starts;
  219. #ttls;
  220. #hasDispose;
  221. #hasFetchMethod;
  222. #hasDisposeAfter;
  223. /**
  224. * Do not call this method unless you need to inspect the
  225. * inner workings of the cache. If anything returned by this
  226. * object is modified in any way, strange breakage may occur.
  227. *
  228. * These fields are private for a reason!
  229. *
  230. * @internal
  231. */
  232. static unsafeExposeInternals(c) {
  233. return {
  234. // properties
  235. starts: c.#starts,
  236. ttls: c.#ttls,
  237. sizes: c.#sizes,
  238. keyMap: c.#keyMap,
  239. keyList: c.#keyList,
  240. valList: c.#valList,
  241. next: c.#next,
  242. prev: c.#prev,
  243. get head() {
  244. return c.#head;
  245. },
  246. get tail() {
  247. return c.#tail;
  248. },
  249. free: c.#free,
  250. // methods
  251. isBackgroundFetch: (p) => c.#isBackgroundFetch(p),
  252. backgroundFetch: (k, index, options, context) => c.#backgroundFetch(k, index, options, context),
  253. moveToTail: (index) => c.#moveToTail(index),
  254. indexes: (options) => c.#indexes(options),
  255. rindexes: (options) => c.#rindexes(options),
  256. isStale: (index) => c.#isStale(index),
  257. };
  258. }
  259. // Protected read-only members
  260. /**
  261. * {@link LRUCache.OptionsBase.max} (read-only)
  262. */
  263. get max() {
  264. return this.#max;
  265. }
  266. /**
  267. * {@link LRUCache.OptionsBase.maxSize} (read-only)
  268. */
  269. get maxSize() {
  270. return this.#maxSize;
  271. }
  272. /**
  273. * The total computed size of items in the cache (read-only)
  274. */
  275. get calculatedSize() {
  276. return this.#calculatedSize;
  277. }
  278. /**
  279. * The number of items stored in the cache (read-only)
  280. */
  281. get size() {
  282. return this.#size;
  283. }
  284. /**
  285. * {@link LRUCache.OptionsBase.fetchMethod} (read-only)
  286. */
  287. get fetchMethod() {
  288. return this.#fetchMethod;
  289. }
  290. /**
  291. * {@link LRUCache.OptionsBase.dispose} (read-only)
  292. */
  293. get dispose() {
  294. return this.#dispose;
  295. }
  296. /**
  297. * {@link LRUCache.OptionsBase.disposeAfter} (read-only)
  298. */
  299. get disposeAfter() {
  300. return this.#disposeAfter;
  301. }
  302. constructor(options) {
  303. const { max = 0, ttl, ttlResolution = 1, ttlAutopurge, updateAgeOnGet, updateAgeOnHas, allowStale, dispose, disposeAfter, noDisposeOnSet, noUpdateTTL, maxSize = 0, maxEntrySize = 0, sizeCalculation, fetchMethod, noDeleteOnFetchRejection, noDeleteOnStaleGet, allowStaleOnFetchRejection, allowStaleOnFetchAbort, ignoreFetchAbort, } = options;
  304. if (max !== 0 && !isPosInt(max)) {
  305. throw new TypeError('max option must be a nonnegative integer');
  306. }
  307. const UintArray = max ? getUintArray(max) : Array;
  308. if (!UintArray) {
  309. throw new Error('invalid max value: ' + max);
  310. }
  311. this.#max = max;
  312. this.#maxSize = maxSize;
  313. this.maxEntrySize = maxEntrySize || this.#maxSize;
  314. this.sizeCalculation = sizeCalculation;
  315. if (this.sizeCalculation) {
  316. if (!this.#maxSize && !this.maxEntrySize) {
  317. throw new TypeError('cannot set sizeCalculation without setting maxSize or maxEntrySize');
  318. }
  319. if (typeof this.sizeCalculation !== 'function') {
  320. throw new TypeError('sizeCalculation set to non-function');
  321. }
  322. }
  323. if (fetchMethod !== undefined &&
  324. typeof fetchMethod !== 'function') {
  325. throw new TypeError('fetchMethod must be a function if specified');
  326. }
  327. this.#fetchMethod = fetchMethod;
  328. this.#hasFetchMethod = !!fetchMethod;
  329. this.#keyMap = new Map();
  330. this.#keyList = new Array(max).fill(undefined);
  331. this.#valList = new Array(max).fill(undefined);
  332. this.#next = new UintArray(max);
  333. this.#prev = new UintArray(max);
  334. this.#head = 0;
  335. this.#tail = 0;
  336. this.#free = Stack.create(max);
  337. this.#size = 0;
  338. this.#calculatedSize = 0;
  339. if (typeof dispose === 'function') {
  340. this.#dispose = dispose;
  341. }
  342. if (typeof disposeAfter === 'function') {
  343. this.#disposeAfter = disposeAfter;
  344. this.#disposed = [];
  345. }
  346. else {
  347. this.#disposeAfter = undefined;
  348. this.#disposed = undefined;
  349. }
  350. this.#hasDispose = !!this.#dispose;
  351. this.#hasDisposeAfter = !!this.#disposeAfter;
  352. this.noDisposeOnSet = !!noDisposeOnSet;
  353. this.noUpdateTTL = !!noUpdateTTL;
  354. this.noDeleteOnFetchRejection = !!noDeleteOnFetchRejection;
  355. this.allowStaleOnFetchRejection = !!allowStaleOnFetchRejection;
  356. this.allowStaleOnFetchAbort = !!allowStaleOnFetchAbort;
  357. this.ignoreFetchAbort = !!ignoreFetchAbort;
  358. // NB: maxEntrySize is set to maxSize if it's set
  359. if (this.maxEntrySize !== 0) {
  360. if (this.#maxSize !== 0) {
  361. if (!isPosInt(this.#maxSize)) {
  362. throw new TypeError('maxSize must be a positive integer if specified');
  363. }
  364. }
  365. if (!isPosInt(this.maxEntrySize)) {
  366. throw new TypeError('maxEntrySize must be a positive integer if specified');
  367. }
  368. this.#initializeSizeTracking();
  369. }
  370. this.allowStale = !!allowStale;
  371. this.noDeleteOnStaleGet = !!noDeleteOnStaleGet;
  372. this.updateAgeOnGet = !!updateAgeOnGet;
  373. this.updateAgeOnHas = !!updateAgeOnHas;
  374. this.ttlResolution =
  375. isPosInt(ttlResolution) || ttlResolution === 0
  376. ? ttlResolution
  377. : 1;
  378. this.ttlAutopurge = !!ttlAutopurge;
  379. this.ttl = ttl || 0;
  380. if (this.ttl) {
  381. if (!isPosInt(this.ttl)) {
  382. throw new TypeError('ttl must be a positive integer if specified');
  383. }
  384. this.#initializeTTLTracking();
  385. }
  386. // do not allow completely unbounded caches
  387. if (this.#max === 0 && this.ttl === 0 && this.#maxSize === 0) {
  388. throw new TypeError('At least one of max, maxSize, or ttl is required');
  389. }
  390. if (!this.ttlAutopurge && !this.#max && !this.#maxSize) {
  391. const code = 'LRU_CACHE_UNBOUNDED';
  392. if (shouldWarn(code)) {
  393. warned.add(code);
  394. const msg = 'TTL caching without ttlAutopurge, max, or maxSize can ' +
  395. 'result in unbounded memory consumption.';
  396. emitWarning(msg, 'UnboundedCacheWarning', code, LRUCache);
  397. }
  398. }
  399. }
  400. /**
  401. * Return the remaining TTL time for a given entry key
  402. */
  403. getRemainingTTL(key) {
  404. return this.#keyMap.has(key) ? Infinity : 0;
  405. }
  406. #initializeTTLTracking() {
  407. const ttls = new ZeroArray(this.#max);
  408. const starts = new ZeroArray(this.#max);
  409. this.#ttls = ttls;
  410. this.#starts = starts;
  411. this.#setItemTTL = (index, ttl, start = perf.now()) => {
  412. starts[index] = ttl !== 0 ? start : 0;
  413. ttls[index] = ttl;
  414. if (ttl !== 0 && this.ttlAutopurge) {
  415. const t = setTimeout(() => {
  416. if (this.#isStale(index)) {
  417. this.delete(this.#keyList[index]);
  418. }
  419. }, ttl + 1);
  420. // unref() not supported on all platforms
  421. /* c8 ignore start */
  422. if (t.unref) {
  423. t.unref();
  424. }
  425. /* c8 ignore stop */
  426. }
  427. };
  428. this.#updateItemAge = index => {
  429. starts[index] = ttls[index] !== 0 ? perf.now() : 0;
  430. };
  431. this.#statusTTL = (status, index) => {
  432. if (ttls[index]) {
  433. const ttl = ttls[index];
  434. const start = starts[index];
  435. /* c8 ignore next */
  436. if (!ttl || !start)
  437. return;
  438. status.ttl = ttl;
  439. status.start = start;
  440. status.now = cachedNow || getNow();
  441. const age = status.now - start;
  442. status.remainingTTL = ttl - age;
  443. }
  444. };
  445. // debounce calls to perf.now() to 1s so we're not hitting
  446. // that costly call repeatedly.
  447. let cachedNow = 0;
  448. const getNow = () => {
  449. const n = perf.now();
  450. if (this.ttlResolution > 0) {
  451. cachedNow = n;
  452. const t = setTimeout(() => (cachedNow = 0), this.ttlResolution);
  453. // not available on all platforms
  454. /* c8 ignore start */
  455. if (t.unref) {
  456. t.unref();
  457. }
  458. /* c8 ignore stop */
  459. }
  460. return n;
  461. };
  462. this.getRemainingTTL = key => {
  463. const index = this.#keyMap.get(key);
  464. if (index === undefined) {
  465. return 0;
  466. }
  467. const ttl = ttls[index];
  468. const start = starts[index];
  469. if (!ttl || !start) {
  470. return Infinity;
  471. }
  472. const age = (cachedNow || getNow()) - start;
  473. return ttl - age;
  474. };
  475. this.#isStale = index => {
  476. const s = starts[index];
  477. const t = ttls[index];
  478. return !!t && !!s && (cachedNow || getNow()) - s > t;
  479. };
  480. }
  481. // conditionally set private methods related to TTL
  482. #updateItemAge = () => { };
  483. #statusTTL = () => { };
  484. #setItemTTL = () => { };
  485. /* c8 ignore stop */
  486. #isStale = () => false;
  487. #initializeSizeTracking() {
  488. const sizes = new ZeroArray(this.#max);
  489. this.#calculatedSize = 0;
  490. this.#sizes = sizes;
  491. this.#removeItemSize = index => {
  492. this.#calculatedSize -= sizes[index];
  493. sizes[index] = 0;
  494. };
  495. this.#requireSize = (k, v, size, sizeCalculation) => {
  496. // provisionally accept background fetches.
  497. // actual value size will be checked when they return.
  498. if (this.#isBackgroundFetch(v)) {
  499. return 0;
  500. }
  501. if (!isPosInt(size)) {
  502. if (sizeCalculation) {
  503. if (typeof sizeCalculation !== 'function') {
  504. throw new TypeError('sizeCalculation must be a function');
  505. }
  506. size = sizeCalculation(v, k);
  507. if (!isPosInt(size)) {
  508. throw new TypeError('sizeCalculation return invalid (expect positive integer)');
  509. }
  510. }
  511. else {
  512. throw new TypeError('invalid size value (must be positive integer). ' +
  513. 'When maxSize or maxEntrySize is used, sizeCalculation ' +
  514. 'or size must be set.');
  515. }
  516. }
  517. return size;
  518. };
  519. this.#addItemSize = (index, size, status) => {
  520. sizes[index] = size;
  521. if (this.#maxSize) {
  522. const maxSize = this.#maxSize - sizes[index];
  523. while (this.#calculatedSize > maxSize) {
  524. this.#evict(true);
  525. }
  526. }
  527. this.#calculatedSize += sizes[index];
  528. if (status) {
  529. status.entrySize = size;
  530. status.totalCalculatedSize = this.#calculatedSize;
  531. }
  532. };
  533. }
  534. #removeItemSize = _i => { };
  535. #addItemSize = (_i, _s, _st) => { };
  536. #requireSize = (_k, _v, size, sizeCalculation) => {
  537. if (size || sizeCalculation) {
  538. throw new TypeError('cannot set size without setting maxSize or maxEntrySize on cache');
  539. }
  540. return 0;
  541. };
  542. *#indexes({ allowStale = this.allowStale } = {}) {
  543. if (this.#size) {
  544. for (let i = this.#tail; true;) {
  545. if (!this.#isValidIndex(i)) {
  546. break;
  547. }
  548. if (allowStale || !this.#isStale(i)) {
  549. yield i;
  550. }
  551. if (i === this.#head) {
  552. break;
  553. }
  554. else {
  555. i = this.#prev[i];
  556. }
  557. }
  558. }
  559. }
  560. *#rindexes({ allowStale = this.allowStale } = {}) {
  561. if (this.#size) {
  562. for (let i = this.#head; true;) {
  563. if (!this.#isValidIndex(i)) {
  564. break;
  565. }
  566. if (allowStale || !this.#isStale(i)) {
  567. yield i;
  568. }
  569. if (i === this.#tail) {
  570. break;
  571. }
  572. else {
  573. i = this.#next[i];
  574. }
  575. }
  576. }
  577. }
  578. #isValidIndex(index) {
  579. return (index !== undefined &&
  580. this.#keyMap.get(this.#keyList[index]) === index);
  581. }
  582. /**
  583. * Return a generator yielding `[key, value]` pairs,
  584. * in order from most recently used to least recently used.
  585. */
  586. *entries() {
  587. for (const i of this.#indexes()) {
  588. if (this.#valList[i] !== undefined &&
  589. this.#keyList[i] !== undefined &&
  590. !this.#isBackgroundFetch(this.#valList[i])) {
  591. yield [this.#keyList[i], this.#valList[i]];
  592. }
  593. }
  594. }
  595. /**
  596. * Inverse order version of {@link LRUCache.entries}
  597. *
  598. * Return a generator yielding `[key, value]` pairs,
  599. * in order from least recently used to most recently used.
  600. */
  601. *rentries() {
  602. for (const i of this.#rindexes()) {
  603. if (this.#valList[i] !== undefined &&
  604. this.#keyList[i] !== undefined &&
  605. !this.#isBackgroundFetch(this.#valList[i])) {
  606. yield [this.#keyList[i], this.#valList[i]];
  607. }
  608. }
  609. }
  610. /**
  611. * Return a generator yielding the keys in the cache,
  612. * in order from most recently used to least recently used.
  613. */
  614. *keys() {
  615. for (const i of this.#indexes()) {
  616. const k = this.#keyList[i];
  617. if (k !== undefined &&
  618. !this.#isBackgroundFetch(this.#valList[i])) {
  619. yield k;
  620. }
  621. }
  622. }
  623. /**
  624. * Inverse order version of {@link LRUCache.keys}
  625. *
  626. * Return a generator yielding the keys in the cache,
  627. * in order from least recently used to most recently used.
  628. */
  629. *rkeys() {
  630. for (const i of this.#rindexes()) {
  631. const k = this.#keyList[i];
  632. if (k !== undefined &&
  633. !this.#isBackgroundFetch(this.#valList[i])) {
  634. yield k;
  635. }
  636. }
  637. }
  638. /**
  639. * Return a generator yielding the values in the cache,
  640. * in order from most recently used to least recently used.
  641. */
  642. *values() {
  643. for (const i of this.#indexes()) {
  644. const v = this.#valList[i];
  645. if (v !== undefined &&
  646. !this.#isBackgroundFetch(this.#valList[i])) {
  647. yield this.#valList[i];
  648. }
  649. }
  650. }
  651. /**
  652. * Inverse order version of {@link LRUCache.values}
  653. *
  654. * Return a generator yielding the values in the cache,
  655. * in order from least recently used to most recently used.
  656. */
  657. *rvalues() {
  658. for (const i of this.#rindexes()) {
  659. const v = this.#valList[i];
  660. if (v !== undefined &&
  661. !this.#isBackgroundFetch(this.#valList[i])) {
  662. yield this.#valList[i];
  663. }
  664. }
  665. }
  666. /**
  667. * Iterating over the cache itself yields the same results as
  668. * {@link LRUCache.entries}
  669. */
  670. [Symbol.iterator]() {
  671. return this.entries();
  672. }
  673. /**
  674. * A String value that is used in the creation of the default string description of an object.
  675. * Called by the built-in method Object.prototype.toString.
  676. */
  677. [Symbol.toStringTag] = 'LRUCache';
  678. /**
  679. * Find a value for which the supplied fn method returns a truthy value,
  680. * similar to Array.find(). fn is called as fn(value, key, cache).
  681. */
  682. find(fn, getOptions = {}) {
  683. for (const i of this.#indexes()) {
  684. const v = this.#valList[i];
  685. const value = this.#isBackgroundFetch(v)
  686. ? v.__staleWhileFetching
  687. : v;
  688. if (value === undefined)
  689. continue;
  690. if (fn(value, this.#keyList[i], this)) {
  691. return this.get(this.#keyList[i], getOptions);
  692. }
  693. }
  694. }
  695. /**
  696. * Call the supplied function on each item in the cache, in order from
  697. * most recently used to least recently used. fn is called as
  698. * fn(value, key, cache). Does not update age or recenty of use.
  699. * Does not iterate over stale values.
  700. */
  701. forEach(fn, thisp = this) {
  702. for (const i of this.#indexes()) {
  703. const v = this.#valList[i];
  704. const value = this.#isBackgroundFetch(v)
  705. ? v.__staleWhileFetching
  706. : v;
  707. if (value === undefined)
  708. continue;
  709. fn.call(thisp, value, this.#keyList[i], this);
  710. }
  711. }
  712. /**
  713. * The same as {@link LRUCache.forEach} but items are iterated over in
  714. * reverse order. (ie, less recently used items are iterated over first.)
  715. */
  716. rforEach(fn, thisp = this) {
  717. for (const i of this.#rindexes()) {
  718. const v = this.#valList[i];
  719. const value = this.#isBackgroundFetch(v)
  720. ? v.__staleWhileFetching
  721. : v;
  722. if (value === undefined)
  723. continue;
  724. fn.call(thisp, value, this.#keyList[i], this);
  725. }
  726. }
  727. /**
  728. * Delete any stale entries. Returns true if anything was removed,
  729. * false otherwise.
  730. */
  731. purgeStale() {
  732. let deleted = false;
  733. for (const i of this.#rindexes({ allowStale: true })) {
  734. if (this.#isStale(i)) {
  735. this.delete(this.#keyList[i]);
  736. deleted = true;
  737. }
  738. }
  739. return deleted;
  740. }
  741. /**
  742. * Get the extended info about a given entry, to get its value, size, and
  743. * TTL info simultaneously. Like {@link LRUCache#dump}, but just for a
  744. * single key. Always returns stale values, if their info is found in the
  745. * cache, so be sure to check for expired TTLs if relevant.
  746. */
  747. info(key) {
  748. const i = this.#keyMap.get(key);
  749. if (i === undefined)
  750. return undefined;
  751. const v = this.#valList[i];
  752. const value = this.#isBackgroundFetch(v)
  753. ? v.__staleWhileFetching
  754. : v;
  755. if (value === undefined)
  756. return undefined;
  757. const entry = { value };
  758. if (this.#ttls && this.#starts) {
  759. const ttl = this.#ttls[i];
  760. const start = this.#starts[i];
  761. if (ttl && start) {
  762. const remain = ttl - (perf.now() - start);
  763. entry.ttl = remain;
  764. entry.start = Date.now();
  765. }
  766. }
  767. if (this.#sizes) {
  768. entry.size = this.#sizes[i];
  769. }
  770. return entry;
  771. }
  772. /**
  773. * Return an array of [key, {@link LRUCache.Entry}] tuples which can be
  774. * passed to cache.load()
  775. */
  776. dump() {
  777. const arr = [];
  778. for (const i of this.#indexes({ allowStale: true })) {
  779. const key = this.#keyList[i];
  780. const v = this.#valList[i];
  781. const value = this.#isBackgroundFetch(v)
  782. ? v.__staleWhileFetching
  783. : v;
  784. if (value === undefined || key === undefined)
  785. continue;
  786. const entry = { value };
  787. if (this.#ttls && this.#starts) {
  788. entry.ttl = this.#ttls[i];
  789. // always dump the start relative to a portable timestamp
  790. // it's ok for this to be a bit slow, it's a rare operation.
  791. const age = perf.now() - this.#starts[i];
  792. entry.start = Math.floor(Date.now() - age);
  793. }
  794. if (this.#sizes) {
  795. entry.size = this.#sizes[i];
  796. }
  797. arr.unshift([key, entry]);
  798. }
  799. return arr;
  800. }
  801. /**
  802. * Reset the cache and load in the items in entries in the order listed.
  803. * Note that the shape of the resulting cache may be different if the
  804. * same options are not used in both caches.
  805. */
  806. load(arr) {
  807. this.clear();
  808. for (const [key, entry] of arr) {
  809. if (entry.start) {
  810. // entry.start is a portable timestamp, but we may be using
  811. // node's performance.now(), so calculate the offset, so that
  812. // we get the intended remaining TTL, no matter how long it's
  813. // been on ice.
  814. //
  815. // it's ok for this to be a bit slow, it's a rare operation.
  816. const age = Date.now() - entry.start;
  817. entry.start = perf.now() - age;
  818. }
  819. this.set(key, entry.value, entry);
  820. }
  821. }
  822. /**
  823. * Add a value to the cache.
  824. *
  825. * Note: if `undefined` is specified as a value, this is an alias for
  826. * {@link LRUCache#delete}
  827. */
  828. set(k, v, setOptions = {}) {
  829. if (v === undefined) {
  830. this.delete(k);
  831. return this;
  832. }
  833. const { ttl = this.ttl, start, noDisposeOnSet = this.noDisposeOnSet, sizeCalculation = this.sizeCalculation, status, } = setOptions;
  834. let { noUpdateTTL = this.noUpdateTTL } = setOptions;
  835. const size = this.#requireSize(k, v, setOptions.size || 0, sizeCalculation);
  836. // if the item doesn't fit, don't do anything
  837. // NB: maxEntrySize set to maxSize by default
  838. if (this.maxEntrySize && size > this.maxEntrySize) {
  839. if (status) {
  840. status.set = 'miss';
  841. status.maxEntrySizeExceeded = true;
  842. }
  843. // have to delete, in case something is there already.
  844. this.delete(k);
  845. return this;
  846. }
  847. let index = this.#size === 0 ? undefined : this.#keyMap.get(k);
  848. if (index === undefined) {
  849. // addition
  850. index = (this.#size === 0
  851. ? this.#tail
  852. : this.#free.length !== 0
  853. ? this.#free.pop()
  854. : this.#size === this.#max
  855. ? this.#evict(false)
  856. : this.#size);
  857. this.#keyList[index] = k;
  858. this.#valList[index] = v;
  859. this.#keyMap.set(k, index);
  860. this.#next[this.#tail] = index;
  861. this.#prev[index] = this.#tail;
  862. this.#tail = index;
  863. this.#size++;
  864. this.#addItemSize(index, size, status);
  865. if (status)
  866. status.set = 'add';
  867. noUpdateTTL = false;
  868. }
  869. else {
  870. // update
  871. this.#moveToTail(index);
  872. const oldVal = this.#valList[index];
  873. if (v !== oldVal) {
  874. if (this.#hasFetchMethod && this.#isBackgroundFetch(oldVal)) {
  875. oldVal.__abortController.abort(new Error('replaced'));
  876. const { __staleWhileFetching: s } = oldVal;
  877. if (s !== undefined && !noDisposeOnSet) {
  878. if (this.#hasDispose) {
  879. this.#dispose?.(s, k, 'set');
  880. }
  881. if (this.#hasDisposeAfter) {
  882. this.#disposed?.push([s, k, 'set']);
  883. }
  884. }
  885. }
  886. else if (!noDisposeOnSet) {
  887. if (this.#hasDispose) {
  888. this.#dispose?.(oldVal, k, 'set');
  889. }
  890. if (this.#hasDisposeAfter) {
  891. this.#disposed?.push([oldVal, k, 'set']);
  892. }
  893. }
  894. this.#removeItemSize(index);
  895. this.#addItemSize(index, size, status);
  896. this.#valList[index] = v;
  897. if (status) {
  898. status.set = 'replace';
  899. const oldValue = oldVal && this.#isBackgroundFetch(oldVal)
  900. ? oldVal.__staleWhileFetching
  901. : oldVal;
  902. if (oldValue !== undefined)
  903. status.oldValue = oldValue;
  904. }
  905. }
  906. else if (status) {
  907. status.set = 'update';
  908. }
  909. }
  910. if (ttl !== 0 && !this.#ttls) {
  911. this.#initializeTTLTracking();
  912. }
  913. if (this.#ttls) {
  914. if (!noUpdateTTL) {
  915. this.#setItemTTL(index, ttl, start);
  916. }
  917. if (status)
  918. this.#statusTTL(status, index);
  919. }
  920. if (!noDisposeOnSet && this.#hasDisposeAfter && this.#disposed) {
  921. const dt = this.#disposed;
  922. let task;
  923. while ((task = dt?.shift())) {
  924. this.#disposeAfter?.(...task);
  925. }
  926. }
  927. return this;
  928. }
  929. /**
  930. * Evict the least recently used item, returning its value or
  931. * `undefined` if cache is empty.
  932. */
  933. pop() {
  934. try {
  935. while (this.#size) {
  936. const val = this.#valList[this.#head];
  937. this.#evict(true);
  938. if (this.#isBackgroundFetch(val)) {
  939. if (val.__staleWhileFetching) {
  940. return val.__staleWhileFetching;
  941. }
  942. }
  943. else if (val !== undefined) {
  944. return val;
  945. }
  946. }
  947. }
  948. finally {
  949. if (this.#hasDisposeAfter && this.#disposed) {
  950. const dt = this.#disposed;
  951. let task;
  952. while ((task = dt?.shift())) {
  953. this.#disposeAfter?.(...task);
  954. }
  955. }
  956. }
  957. }
  958. #evict(free) {
  959. const head = this.#head;
  960. const k = this.#keyList[head];
  961. const v = this.#valList[head];
  962. if (this.#hasFetchMethod && this.#isBackgroundFetch(v)) {
  963. v.__abortController.abort(new Error('evicted'));
  964. }
  965. else if (this.#hasDispose || this.#hasDisposeAfter) {
  966. if (this.#hasDispose) {
  967. this.#dispose?.(v, k, 'evict');
  968. }
  969. if (this.#hasDisposeAfter) {
  970. this.#disposed?.push([v, k, 'evict']);
  971. }
  972. }
  973. this.#removeItemSize(head);
  974. // if we aren't about to use the index, then null these out
  975. if (free) {
  976. this.#keyList[head] = undefined;
  977. this.#valList[head] = undefined;
  978. this.#free.push(head);
  979. }
  980. if (this.#size === 1) {
  981. this.#head = this.#tail = 0;
  982. this.#free.length = 0;
  983. }
  984. else {
  985. this.#head = this.#next[head];
  986. }
  987. this.#keyMap.delete(k);
  988. this.#size--;
  989. return head;
  990. }
  991. /**
  992. * Check if a key is in the cache, without updating the recency of use.
  993. * Will return false if the item is stale, even though it is technically
  994. * in the cache.
  995. *
  996. * Will not update item age unless
  997. * {@link LRUCache.OptionsBase.updateAgeOnHas} is set.
  998. */
  999. has(k, hasOptions = {}) {
  1000. const { updateAgeOnHas = this.updateAgeOnHas, status } = hasOptions;
  1001. const index = this.#keyMap.get(k);
  1002. if (index !== undefined) {
  1003. const v = this.#valList[index];
  1004. if (this.#isBackgroundFetch(v) &&
  1005. v.__staleWhileFetching === undefined) {
  1006. return false;
  1007. }
  1008. if (!this.#isStale(index)) {
  1009. if (updateAgeOnHas) {
  1010. this.#updateItemAge(index);
  1011. }
  1012. if (status) {
  1013. status.has = 'hit';
  1014. this.#statusTTL(status, index);
  1015. }
  1016. return true;
  1017. }
  1018. else if (status) {
  1019. status.has = 'stale';
  1020. this.#statusTTL(status, index);
  1021. }
  1022. }
  1023. else if (status) {
  1024. status.has = 'miss';
  1025. }
  1026. return false;
  1027. }
  1028. /**
  1029. * Like {@link LRUCache#get} but doesn't update recency or delete stale
  1030. * items.
  1031. *
  1032. * Returns `undefined` if the item is stale, unless
  1033. * {@link LRUCache.OptionsBase.allowStale} is set.
  1034. */
  1035. peek(k, peekOptions = {}) {
  1036. const { allowStale = this.allowStale } = peekOptions;
  1037. const index = this.#keyMap.get(k);
  1038. if (index === undefined ||
  1039. (!allowStale && this.#isStale(index))) {
  1040. return;
  1041. }
  1042. const v = this.#valList[index];
  1043. // either stale and allowed, or forcing a refresh of non-stale value
  1044. return this.#isBackgroundFetch(v) ? v.__staleWhileFetching : v;
  1045. }
  1046. #backgroundFetch(k, index, options, context) {
  1047. const v = index === undefined ? undefined : this.#valList[index];
  1048. if (this.#isBackgroundFetch(v)) {
  1049. return v;
  1050. }
  1051. const ac = new AC();
  1052. const { signal } = options;
  1053. // when/if our AC signals, then stop listening to theirs.
  1054. signal?.addEventListener('abort', () => ac.abort(signal.reason), {
  1055. signal: ac.signal,
  1056. });
  1057. const fetchOpts = {
  1058. signal: ac.signal,
  1059. options,
  1060. context,
  1061. };
  1062. const cb = (v, updateCache = false) => {
  1063. const { aborted } = ac.signal;
  1064. const ignoreAbort = options.ignoreFetchAbort && v !== undefined;
  1065. if (options.status) {
  1066. if (aborted && !updateCache) {
  1067. options.status.fetchAborted = true;
  1068. options.status.fetchError = ac.signal.reason;
  1069. if (ignoreAbort)
  1070. options.status.fetchAbortIgnored = true;
  1071. }
  1072. else {
  1073. options.status.fetchResolved = true;
  1074. }
  1075. }
  1076. if (aborted && !ignoreAbort && !updateCache) {
  1077. return fetchFail(ac.signal.reason);
  1078. }
  1079. // either we didn't abort, and are still here, or we did, and ignored
  1080. const bf = p;
  1081. if (this.#valList[index] === p) {
  1082. if (v === undefined) {
  1083. if (bf.__staleWhileFetching) {
  1084. this.#valList[index] = bf.__staleWhileFetching;
  1085. }
  1086. else {
  1087. this.delete(k);
  1088. }
  1089. }
  1090. else {
  1091. if (options.status)
  1092. options.status.fetchUpdated = true;
  1093. this.set(k, v, fetchOpts.options);
  1094. }
  1095. }
  1096. return v;
  1097. };
  1098. const eb = (er) => {
  1099. if (options.status) {
  1100. options.status.fetchRejected = true;
  1101. options.status.fetchError = er;
  1102. }
  1103. return fetchFail(er);
  1104. };
  1105. const fetchFail = (er) => {
  1106. const { aborted } = ac.signal;
  1107. const allowStaleAborted = aborted && options.allowStaleOnFetchAbort;
  1108. const allowStale = allowStaleAborted || options.allowStaleOnFetchRejection;
  1109. const noDelete = allowStale || options.noDeleteOnFetchRejection;
  1110. const bf = p;
  1111. if (this.#valList[index] === p) {
  1112. // if we allow stale on fetch rejections, then we need to ensure that
  1113. // the stale value is not removed from the cache when the fetch fails.
  1114. const del = !noDelete || bf.__staleWhileFetching === undefined;
  1115. if (del) {
  1116. this.delete(k);
  1117. }
  1118. else if (!allowStaleAborted) {
  1119. // still replace the *promise* with the stale value,
  1120. // since we are done with the promise at this point.
  1121. // leave it untouched if we're still waiting for an
  1122. // aborted background fetch that hasn't yet returned.
  1123. this.#valList[index] = bf.__staleWhileFetching;
  1124. }
  1125. }
  1126. if (allowStale) {
  1127. if (options.status && bf.__staleWhileFetching !== undefined) {
  1128. options.status.returnedStale = true;
  1129. }
  1130. return bf.__staleWhileFetching;
  1131. }
  1132. else if (bf.__returned === bf) {
  1133. throw er;
  1134. }
  1135. };
  1136. const pcall = (res, rej) => {
  1137. const fmp = this.#fetchMethod?.(k, v, fetchOpts);
  1138. if (fmp && fmp instanceof Promise) {
  1139. fmp.then(v => res(v === undefined ? undefined : v), rej);
  1140. }
  1141. // ignored, we go until we finish, regardless.
  1142. // defer check until we are actually aborting,
  1143. // so fetchMethod can override.
  1144. ac.signal.addEventListener('abort', () => {
  1145. if (!options.ignoreFetchAbort ||
  1146. options.allowStaleOnFetchAbort) {
  1147. res(undefined);
  1148. // when it eventually resolves, update the cache.
  1149. if (options.allowStaleOnFetchAbort) {
  1150. res = v => cb(v, true);
  1151. }
  1152. }
  1153. });
  1154. };
  1155. if (options.status)
  1156. options.status.fetchDispatched = true;
  1157. const p = new Promise(pcall).then(cb, eb);
  1158. const bf = Object.assign(p, {
  1159. __abortController: ac,
  1160. __staleWhileFetching: v,
  1161. __returned: undefined,
  1162. });
  1163. if (index === undefined) {
  1164. // internal, don't expose status.
  1165. this.set(k, bf, { ...fetchOpts.options, status: undefined });
  1166. index = this.#keyMap.get(k);
  1167. }
  1168. else {
  1169. this.#valList[index] = bf;
  1170. }
  1171. return bf;
  1172. }
  1173. #isBackgroundFetch(p) {
  1174. if (!this.#hasFetchMethod)
  1175. return false;
  1176. const b = p;
  1177. return (!!b &&
  1178. b instanceof Promise &&
  1179. b.hasOwnProperty('__staleWhileFetching') &&
  1180. b.__abortController instanceof AC);
  1181. }
  1182. async fetch(k, fetchOptions = {}) {
  1183. const {
  1184. // get options
  1185. allowStale = this.allowStale, updateAgeOnGet = this.updateAgeOnGet, noDeleteOnStaleGet = this.noDeleteOnStaleGet,
  1186. // set options
  1187. ttl = this.ttl, noDisposeOnSet = this.noDisposeOnSet, size = 0, sizeCalculation = this.sizeCalculation, noUpdateTTL = this.noUpdateTTL,
  1188. // fetch exclusive options
  1189. noDeleteOnFetchRejection = this.noDeleteOnFetchRejection, allowStaleOnFetchRejection = this.allowStaleOnFetchRejection, ignoreFetchAbort = this.ignoreFetchAbort, allowStaleOnFetchAbort = this.allowStaleOnFetchAbort, context, forceRefresh = false, status, signal, } = fetchOptions;
  1190. if (!this.#hasFetchMethod) {
  1191. if (status)
  1192. status.fetch = 'get';
  1193. return this.get(k, {
  1194. allowStale,
  1195. updateAgeOnGet,
  1196. noDeleteOnStaleGet,
  1197. status,
  1198. });
  1199. }
  1200. const options = {
  1201. allowStale,
  1202. updateAgeOnGet,
  1203. noDeleteOnStaleGet,
  1204. ttl,
  1205. noDisposeOnSet,
  1206. size,
  1207. sizeCalculation,
  1208. noUpdateTTL,
  1209. noDeleteOnFetchRejection,
  1210. allowStaleOnFetchRejection,
  1211. allowStaleOnFetchAbort,
  1212. ignoreFetchAbort,
  1213. status,
  1214. signal,
  1215. };
  1216. let index = this.#keyMap.get(k);
  1217. if (index === undefined) {
  1218. if (status)
  1219. status.fetch = 'miss';
  1220. const p = this.#backgroundFetch(k, index, options, context);
  1221. return (p.__returned = p);
  1222. }
  1223. else {
  1224. // in cache, maybe already fetching
  1225. const v = this.#valList[index];
  1226. if (this.#isBackgroundFetch(v)) {
  1227. const stale = allowStale && v.__staleWhileFetching !== undefined;
  1228. if (status) {
  1229. status.fetch = 'inflight';
  1230. if (stale)
  1231. status.returnedStale = true;
  1232. }
  1233. return stale ? v.__staleWhileFetching : (v.__returned = v);
  1234. }
  1235. // if we force a refresh, that means do NOT serve the cached value,
  1236. // unless we are already in the process of refreshing the cache.
  1237. const isStale = this.#isStale(index);
  1238. if (!forceRefresh && !isStale) {
  1239. if (status)
  1240. status.fetch = 'hit';
  1241. this.#moveToTail(index);
  1242. if (updateAgeOnGet) {
  1243. this.#updateItemAge(index);
  1244. }
  1245. if (status)
  1246. this.#statusTTL(status, index);
  1247. return v;
  1248. }
  1249. // ok, it is stale or a forced refresh, and not already fetching.
  1250. // refresh the cache.
  1251. const p = this.#backgroundFetch(k, index, options, context);
  1252. const hasStale = p.__staleWhileFetching !== undefined;
  1253. const staleVal = hasStale && allowStale;
  1254. if (status) {
  1255. status.fetch = isStale ? 'stale' : 'refresh';
  1256. if (staleVal && isStale)
  1257. status.returnedStale = true;
  1258. }
  1259. return staleVal ? p.__staleWhileFetching : (p.__returned = p);
  1260. }
  1261. }
  1262. /**
  1263. * Return a value from the cache. Will update the recency of the cache
  1264. * entry found.
  1265. *
  1266. * If the key is not found, get() will return `undefined`.
  1267. */
  1268. get(k, getOptions = {}) {
  1269. const { allowStale = this.allowStale, updateAgeOnGet = this.updateAgeOnGet, noDeleteOnStaleGet = this.noDeleteOnStaleGet, status, } = getOptions;
  1270. const index = this.#keyMap.get(k);
  1271. if (index !== undefined) {
  1272. const value = this.#valList[index];
  1273. const fetching = this.#isBackgroundFetch(value);
  1274. if (status)
  1275. this.#statusTTL(status, index);
  1276. if (this.#isStale(index)) {
  1277. if (status)
  1278. status.get = 'stale';
  1279. // delete only if not an in-flight background fetch
  1280. if (!fetching) {
  1281. if (!noDeleteOnStaleGet) {
  1282. this.delete(k);
  1283. }
  1284. if (status && allowStale)
  1285. status.returnedStale = true;
  1286. return allowStale ? value : undefined;
  1287. }
  1288. else {
  1289. if (status &&
  1290. allowStale &&
  1291. value.__staleWhileFetching !== undefined) {
  1292. status.returnedStale = true;
  1293. }
  1294. return allowStale ? value.__staleWhileFetching : undefined;
  1295. }
  1296. }
  1297. else {
  1298. if (status)
  1299. status.get = 'hit';
  1300. // if we're currently fetching it, we don't actually have it yet
  1301. // it's not stale, which means this isn't a staleWhileRefetching.
  1302. // If it's not stale, and fetching, AND has a __staleWhileFetching
  1303. // value, then that means the user fetched with {forceRefresh:true},
  1304. // so it's safe to return that value.
  1305. if (fetching) {
  1306. return value.__staleWhileFetching;
  1307. }
  1308. this.#moveToTail(index);
  1309. if (updateAgeOnGet) {
  1310. this.#updateItemAge(index);
  1311. }
  1312. return value;
  1313. }
  1314. }
  1315. else if (status) {
  1316. status.get = 'miss';
  1317. }
  1318. }
  1319. #connect(p, n) {
  1320. this.#prev[n] = p;
  1321. this.#next[p] = n;
  1322. }
  1323. #moveToTail(index) {
  1324. // if tail already, nothing to do
  1325. // if head, move head to next[index]
  1326. // else
  1327. // move next[prev[index]] to next[index] (head has no prev)
  1328. // move prev[next[index]] to prev[index]
  1329. // prev[index] = tail
  1330. // next[tail] = index
  1331. // tail = index
  1332. if (index !== this.#tail) {
  1333. if (index === this.#head) {
  1334. this.#head = this.#next[index];
  1335. }
  1336. else {
  1337. this.#connect(this.#prev[index], this.#next[index]);
  1338. }
  1339. this.#connect(this.#tail, index);
  1340. this.#tail = index;
  1341. }
  1342. }
  1343. /**
  1344. * Deletes a key out of the cache.
  1345. * Returns true if the key was deleted, false otherwise.
  1346. */
  1347. delete(k) {
  1348. let deleted = false;
  1349. if (this.#size !== 0) {
  1350. const index = this.#keyMap.get(k);
  1351. if (index !== undefined) {
  1352. deleted = true;
  1353. if (this.#size === 1) {
  1354. this.clear();
  1355. }
  1356. else {
  1357. this.#removeItemSize(index);
  1358. const v = this.#valList[index];
  1359. if (this.#isBackgroundFetch(v)) {
  1360. v.__abortController.abort(new Error('deleted'));
  1361. }
  1362. else if (this.#hasDispose || this.#hasDisposeAfter) {
  1363. if (this.#hasDispose) {
  1364. this.#dispose?.(v, k, 'delete');
  1365. }
  1366. if (this.#hasDisposeAfter) {
  1367. this.#disposed?.push([v, k, 'delete']);
  1368. }
  1369. }
  1370. this.#keyMap.delete(k);
  1371. this.#keyList[index] = undefined;
  1372. this.#valList[index] = undefined;
  1373. if (index === this.#tail) {
  1374. this.#tail = this.#prev[index];
  1375. }
  1376. else if (index === this.#head) {
  1377. this.#head = this.#next[index];
  1378. }
  1379. else {
  1380. const pi = this.#prev[index];
  1381. this.#next[pi] = this.#next[index];
  1382. const ni = this.#next[index];
  1383. this.#prev[ni] = this.#prev[index];
  1384. }
  1385. this.#size--;
  1386. this.#free.push(index);
  1387. }
  1388. }
  1389. }
  1390. if (this.#hasDisposeAfter && this.#disposed?.length) {
  1391. const dt = this.#disposed;
  1392. let task;
  1393. while ((task = dt?.shift())) {
  1394. this.#disposeAfter?.(...task);
  1395. }
  1396. }
  1397. return deleted;
  1398. }
  1399. /**
  1400. * Clear the cache entirely, throwing away all values.
  1401. */
  1402. clear() {
  1403. for (const index of this.#rindexes({ allowStale: true })) {
  1404. const v = this.#valList[index];
  1405. if (this.#isBackgroundFetch(v)) {
  1406. v.__abortController.abort(new Error('deleted'));
  1407. }
  1408. else {
  1409. const k = this.#keyList[index];
  1410. if (this.#hasDispose) {
  1411. this.#dispose?.(v, k, 'delete');
  1412. }
  1413. if (this.#hasDisposeAfter) {
  1414. this.#disposed?.push([v, k, 'delete']);
  1415. }
  1416. }
  1417. }
  1418. this.#keyMap.clear();
  1419. this.#valList.fill(undefined);
  1420. this.#keyList.fill(undefined);
  1421. if (this.#ttls && this.#starts) {
  1422. this.#ttls.fill(0);
  1423. this.#starts.fill(0);
  1424. }
  1425. if (this.#sizes) {
  1426. this.#sizes.fill(0);
  1427. }
  1428. this.#head = 0;
  1429. this.#tail = 0;
  1430. this.#free.length = 0;
  1431. this.#calculatedSize = 0;
  1432. this.#size = 0;
  1433. if (this.#hasDisposeAfter && this.#disposed) {
  1434. const dt = this.#disposed;
  1435. let task;
  1436. while ((task = dt?.shift())) {
  1437. this.#disposeAfter?.(...task);
  1438. }
  1439. }
  1440. }
  1441. }
  1442. //# sourceMappingURL=index.js.map