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'use strict';
class QuickLRU {
constructor(opts) {
opts = Object.assign({}, opts);
if (!(opts.maxSize && opts.maxSize > 0)) {
throw new TypeError('`maxSize` must be a number greater than 0');
}
this.maxSize = opts.maxSize;
this.cache = new Map();
this.oldCache = new Map();
this._size = 0;
}
_set(key, value) {
this.cache.set(key, value);
this._size++;
if (this._size >= this.maxSize) {
this._size = 0;
this.oldCache = this.cache;
this.cache = new Map();
}
}
get(key) {
if (this.cache.has(key)) {
return this.cache.get(key);
}
if (this.oldCache.has(key)) {
const value = this.oldCache.get(key);
this._set(key, value);
return value;
}
}
set(key, value) {
if (this.cache.has(key)) {
this.cache.set(key, value);
} else {
this._set(key, value);
}
return this;
}
has(key) {
return this.cache.has(key) || this.oldCache.has(key);
}
peek(key) {
if (this.cache.has(key)) {
return this.cache.get(key);
}
if (this.oldCache.has(key)) {
return this.oldCache.get(key);
}
}
delete(key) {
if (this.cache.delete(key)) {
this._size--;
}
this.oldCache.delete(key);
}
clear() {
this.cache.clear();
this.oldCache.clear();
this._size = 0;
}
* keys() {
for (const el of this) {
yield el[0];
}
}
* values() {
for (const el of this) {
yield el[1];
}
}
* [Symbol.iterator]() {
for (const el of this.cache) {
yield el;
}
for (const el of this.oldCache) {
if (!this.cache.has(el[0])) {
yield el;
}
}
}
get size() {
let oldCacheSize = 0;
for (const el of this.oldCache) {
if (!this.cache.has(el[0])) {
oldCacheSize++;
}
}
return this._size + oldCacheSize;
}
}
module.exports = QuickLRU;
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