You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
123 lines
2.0 KiB
123 lines
2.0 KiB
'use strict'; |
|
|
|
class QuickLRU { |
|
constructor(options = {}) { |
|
if (!(options.maxSize && options.maxSize > 0)) { |
|
throw new TypeError('`maxSize` must be a number greater than 0'); |
|
} |
|
|
|
this.maxSize = options.maxSize; |
|
this.onEviction = options.onEviction; |
|
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; |
|
|
|
if (typeof this.onEviction === 'function') { |
|
for (const [key, value] of this.oldCache.entries()) { |
|
this.onEviction(key, value); |
|
} |
|
} |
|
|
|
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.oldCache.delete(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) { |
|
const deleted = this.cache.delete(key); |
|
if (deleted) { |
|
this._size--; |
|
} |
|
|
|
return this.oldCache.delete(key) || deleted; |
|
} |
|
|
|
clear() { |
|
this.cache.clear(); |
|
this.oldCache.clear(); |
|
this._size = 0; |
|
} |
|
|
|
* keys() { |
|
for (const [key] of this) { |
|
yield key; |
|
} |
|
} |
|
|
|
* values() { |
|
for (const [, value] of this) { |
|
yield value; |
|
} |
|
} |
|
|
|
* [Symbol.iterator]() { |
|
for (const item of this.cache) { |
|
yield item; |
|
} |
|
|
|
for (const item of this.oldCache) { |
|
const [key] = item; |
|
if (!this.cache.has(key)) { |
|
yield item; |
|
} |
|
} |
|
} |
|
|
|
get size() { |
|
let oldCacheSize = 0; |
|
for (const key of this.oldCache.keys()) { |
|
if (!this.cache.has(key)) { |
|
oldCacheSize++; |
|
} |
|
} |
|
|
|
return Math.min(this._size + oldCacheSize, this.maxSize); |
|
} |
|
} |
|
|
|
module.exports = QuickLRU;
|
|
|