AK-21/Graphite-Industrial-Intelligence

1'use strict';2 3class QuickLRU {4	constructor(options = {}) {5		if (!(options.maxSize && options.maxSize > 0)) {6			throw new TypeError('`maxSize` must be a number greater than 0');7		}8 9		if (typeof options.maxAge === 'number' && options.maxAge === 0) {10			throw new TypeError('`maxAge` must be a number greater than 0');11		}12 13		this.maxSize = options.maxSize;14		this.maxAge = options.maxAge || Infinity;15		this.onEviction = options.onEviction;16		this.cache = new Map();17		this.oldCache = new Map();18		this._size = 0;19	}20 21	_emitEvictions(cache) {22		if (typeof this.onEviction !== 'function') {23			return;24		}25 26		for (const [key, item] of cache) {27			this.onEviction(key, item.value);28		}29	}30 31	_deleteIfExpired(key, item) {32		if (typeof item.expiry === 'number' && item.expiry <= Date.now()) {33			if (typeof this.onEviction === 'function') {34				this.onEviction(key, item.value);35			}36 37			return this.delete(key);38		}39 40		return false;41	}42 43	_getOrDeleteIfExpired(key, item) {44		const deleted = this._deleteIfExpired(key, item);45		if (deleted === false) {46			return item.value;47		}48	}49 50	_getItemValue(key, item) {51		return item.expiry ? this._getOrDeleteIfExpired(key, item) : item.value;52	}53 54	_peek(key, cache) {55		const item = cache.get(key);56 57		return this._getItemValue(key, item);58	}59 60	_set(key, value) {61		this.cache.set(key, value);62		this._size++;63 64		if (this._size >= this.maxSize) {65			this._size = 0;66			this._emitEvictions(this.oldCache);67			this.oldCache = this.cache;68			this.cache = new Map();69		}70	}71 72	_moveToRecent(key, item) {73		this.oldCache.delete(key);74		this._set(key, item);75	}76 77	* _entriesAscending() {78		for (const item of this.oldCache) {79			const [key, value] = item;80			if (!this.cache.has(key)) {81				const deleted = this._deleteIfExpired(key, value);82				if (deleted === false) {83					yield item;84				}85			}86		}87 88		for (const item of this.cache) {89			const [key, value] = item;90			const deleted = this._deleteIfExpired(key, value);91			if (deleted === false) {92				yield item;93			}94		}95	}96 97	get(key) {98		if (this.cache.has(key)) {99			const item = this.cache.get(key);100 101			return this._getItemValue(key, item);102		}103 104		if (this.oldCache.has(key)) {105			const item = this.oldCache.get(key);106			if (this._deleteIfExpired(key, item) === false) {107				this._moveToRecent(key, item);108				return item.value;109			}110		}111	}112 113	set(key, value, {maxAge = this.maxAge === Infinity ? undefined : Date.now() + this.maxAge} = {}) {114		if (this.cache.has(key)) {115			this.cache.set(key, {116				value,117				maxAge118			});119		} else {120			this._set(key, {value, expiry: maxAge});121		}122	}123 124	has(key) {125		if (this.cache.has(key)) {126			return !this._deleteIfExpired(key, this.cache.get(key));127		}128 129		if (this.oldCache.has(key)) {130			return !this._deleteIfExpired(key, this.oldCache.get(key));131		}132 133		return false;134	}135 136	peek(key) {137		if (this.cache.has(key)) {138			return this._peek(key, this.cache);139		}140 141		if (this.oldCache.has(key)) {142			return this._peek(key, this.oldCache);143		}144	}145 146	delete(key) {147		const deleted = this.cache.delete(key);148		if (deleted) {149			this._size--;150		}151 152		return this.oldCache.delete(key) || deleted;153	}154 155	clear() {156		this.cache.clear();157		this.oldCache.clear();158		this._size = 0;159	}160	161	resize(newSize) {162		if (!(newSize && newSize > 0)) {163			throw new TypeError('`maxSize` must be a number greater than 0');164		}165 166		const items = [...this._entriesAscending()];167		const removeCount = items.length - newSize;168		if (removeCount < 0) {169			this.cache = new Map(items);170			this.oldCache = new Map();171			this._size = items.length;172		} else {173			if (removeCount > 0) {174				this._emitEvictions(items.slice(0, removeCount));175			}176 177			this.oldCache = new Map(items.slice(removeCount));178			this.cache = new Map();179			this._size = 0;180		}181 182		this.maxSize = newSize;183	}184 185	* keys() {186		for (const [key] of this) {187			yield key;188		}189	}190 191	* values() {192		for (const [, value] of this) {193			yield value;194		}195	}196 197	* [Symbol.iterator]() {198		for (const item of this.cache) {199			const [key, value] = item;200			const deleted = this._deleteIfExpired(key, value);201			if (deleted === false) {202				yield [key, value.value];203			}204		}205 206		for (const item of this.oldCache) {207			const [key, value] = item;208			if (!this.cache.has(key)) {209				const deleted = this._deleteIfExpired(key, value);210				if (deleted === false) {211					yield [key, value.value];212				}213			}214		}215	}216 217	* entriesDescending() {218		let items = [...this.cache];219		for (let i = items.length - 1; i >= 0; --i) {220			const item = items[i];221			const [key, value] = item;222			const deleted = this._deleteIfExpired(key, value);223			if (deleted === false) {224				yield [key, value.value];225			}226		}227 228		items = [...this.oldCache];229		for (let i = items.length - 1; i >= 0; --i) {230			const item = items[i];231			const [key, value] = item;232			if (!this.cache.has(key)) {233				const deleted = this._deleteIfExpired(key, value);234				if (deleted === false) {235					yield [key, value.value];236				}237			}238		}239	}240 241	* entriesAscending() {242		for (const [key, value] of this._entriesAscending()) {243			yield [key, value.value];244		}245	}246 247	get size() {248		if (!this._size) {249			return this.oldCache.size;250		}251 252		let oldCacheSize = 0;253		for (const key of this.oldCache.keys()) {254			if (!this.cache.has(key)) {255				oldCacheSize++;256			}257		}258 259		return Math.min(this._size + oldCacheSize, this.maxSize);260	}261}262 263module.exports = QuickLRU;264