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Added LRU support to cache
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This commit is contained in:
Zakary Timson
2025-09-08 22:52:01 -04:00
parent 5849a97c21
commit 751177c981
3 changed files with 182 additions and 57 deletions
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130
src/cache.ts
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@@ -8,6 +8,8 @@ export type CacheOptions = {
persistentStorage?: {storage: Storage | Database, key: string} | string;
/** Keep or delete cached items once expired, defaults to delete */
expiryPolicy?: 'delete' | 'keep';
/** Least Recently Used size limit */
sizeLimit?: number;
}
export type CachedValue<T> = T & {_expired?: boolean};
@@ -16,14 +18,15 @@ export type CachedValue<T> = T & {_expired?: boolean};
* Map of data which tracks whether it is a complete collection & offers optional expiry of cached values
*/
export class Cache<K extends string | number | symbol, T> {
private store: Record<K, T> = <any>{};
private _loading!: Function;
private store: Map<K, T> = new Map();
private timers: Map<K, NodeJS.Timeout> = new Map();
private lruOrder: K[] = [];
/** Support index lookups */
[key: string | number | symbol]: CachedValue<T> | any;
/** Whether cache is complete */
complete = false;
private _loading!: Function;
/** Await initial loading */
loading = new Promise<void>(r => this._loading = r);
@@ -43,12 +46,18 @@ export class Cache<K extends string | number | symbol, T> {
const persists: any = this.options.persistentStorage;
const table: Table<any, any> = await persists.storage.createTable({name: persists.key, key: this.key});
const rows = await table.getAll();
Object.assign(this.store, rows.reduce((acc, row) => ({...acc, [this.getKey(row)]: row}), {}));
for(const row of rows) this.store.set(this.getKey(row), row);
this._loading();
})();
} else if((<any>this.options.persistentStorage?.storage)?.getItem != undefined) {
const stored = (<Storage>this.options.persistentStorage.storage).getItem(this.options.persistentStorage.key);
if(stored != null) try { Object.assign(this.store, JSON.parse(stored)); } catch { }
const {storage, key} = <{storage: Storage, key: string}>this.options.persistentStorage;
const stored = storage.getItem(key);
if(stored != null) {
try {
const obj = JSON.parse(stored);
for(const k of Object.keys(obj)) this.store.set(<any>k, obj[k]);
} catch { /* ignore */ }
}
this._loading();
}
} else {
@@ -71,8 +80,8 @@ export class Cache<K extends string | number | symbol, T> {
private getKey(value: T): K {
if(!this.key) throw new Error('No key defined');
if(value[this.key] === undefined) throw new Error(`${this.key.toString()} Doesn't exist on ${JSON.stringify(value, null, 2)}`);
return <K>value[this.key];
if((value as any)[this.key] === undefined) throw new Error(`${this.key.toString()} Doesn't exist on ${JSON.stringify(value, null, 2)}`);
return <K>(value as any)[this.key];
}
private save(key?: K) {
@@ -80,28 +89,50 @@ export class Cache<K extends string | number | symbol, T> {
if(!!persists?.storage) {
if(persists.storage?.database != undefined) {
(<Database>persists.storage).createTable({name: persists.key, key: <string>this.key}).then(table => {
if(key) {
const value = this.get(key);
if(key !== undefined) {
const value = this.get(key, true);
if(value != null) table.set(value, key);
else table.delete(key);
} else {
table.clear();
this.all().forEach(row => table.add(row));
this.all(true).forEach(row => table.add(row));
}
});
} else if(persists.storage?.setItem != undefined) {
persists.storage.setItem(persists.storage.key, JSONSanitize(this.all(true)));
const obj: Record<any, any> = {};
for(const [k, v] of this.store.entries()) obj[k as any] = v;
persists.storage.setItem(persists.key, JSONSanitize(obj));
}
}
}
private clearTimer(key: K) {
const t = this.timers.get(key);
if(t) { clearTimeout(t); this.timers.delete(key); }
}
private touchLRU(key: K) {
if(!this.options.sizeLimit || this.options.sizeLimit <= 0) return;
const idx = this.lruOrder.indexOf(key);
if(idx >= 0) this.lruOrder.splice(idx, 1);
this.lruOrder.push(key);
while(this.lruOrder.length > (this.options.sizeLimit || 0)) {
const lru = this.lruOrder.shift();
if(lru !== undefined) this.delete(lru);
}
}
/**
* Get all cached items
* @return {T[]} Array of items
*/
all(expired?: boolean): CachedValue<T>[] {
return deepCopy<any>(Object.values(this.store)
.filter((v: any) => expired || !v._expired));
const out: CachedValue<T>[] = [];
for(const v of this.store.values()) {
const val: any = v;
if(expired || !val?._expired) out.push(deepCopy<any>(val));
}
return out;
}
/**
@@ -134,7 +165,10 @@ export class Cache<K extends string | number | symbol, T> {
*/
clear(): this {
this.complete = false;
this.store = <any>{};
for (const [k, t] of this.timers) clearTimeout(t);
this.timers.clear();
this.lruOrder = [];
this.store.clear();
this.save();
return this;
}
@@ -144,7 +178,10 @@ export class Cache<K extends string | number | symbol, T> {
* @param {K} key Item's primary key
*/
delete(key: K): this {
delete this.store[key];
this.clearTimer(key);
const idx = this.lruOrder.indexOf(key);
if(idx >= 0) this.lruOrder.splice(idx, 1);
this.store.delete(key);
this.save(key);
return this;
}
@@ -154,8 +191,12 @@ export class Cache<K extends string | number | symbol, T> {
* @return {[K, T][]} Key-value pairs array
*/
entries(expired?: boolean): [K, CachedValue<T>][] {
return deepCopy<any>(Object.entries(this.store)
.filter((v: any) => expired || !v?._expired));
const out: [K, CachedValue<T>][] = [];
for(const [k, v] of this.store.entries()) {
const val: any = v;
if(expired || !val?._expired) out.push([k, deepCopy<any>(val)]);
}
return out;
}
/**
@@ -165,8 +206,12 @@ export class Cache<K extends string | number | symbol, T> {
expire(key: K): this {
this.complete = false;
if(this.options.expiryPolicy == 'keep') {
(<any>this.store[key])._expired = true;
this.save(key);
const v: any = this.store.get(key);
if(v) {
v._expired = true;
this.store.set(key, v);
this.save(key);
}
} else this.delete(key);
return this;
}
@@ -178,7 +223,11 @@ export class Cache<K extends string | number | symbol, T> {
* @returns {T | undefined} Cached item or undefined if nothing matched
*/
find(filter: Partial<T>, expired?: boolean): T | undefined {
return <T>Object.values(this.store).find((row: any) => (expired || !row._expired) && includes(row, filter));
for(const v of this.store.values()) {
const row: any = v;
if((expired || !row._expired) && includes(row, filter)) return deepCopy<any>(row);
}
return undefined;
}
/**
@@ -188,7 +237,10 @@ export class Cache<K extends string | number | symbol, T> {
* @return {T} Cached item
*/
get(key: K, expired?: boolean): CachedValue<T> | null {
const cached = deepCopy<any>(this.store[key] ?? null);
const raw = this.store.get(key);
if(raw == null) return null;
const cached: any = deepCopy<any>(raw);
this.touchLRU(key);
if(expired || !cached?._expired) return cached;
return null;
}
@@ -198,8 +250,12 @@ export class Cache<K extends string | number | symbol, T> {
* @return {K[]} Array of keys
*/
keys(expired?: boolean): K[] {
return <K[]>Object.keys(this.store)
.filter(k => expired || !(<any>this.store)[k]._expired);
const out: K[] = [];
for(const [k, v] of this.store.entries()) {
const val: any = v;
if(expired || !val?._expired) out.push(k);
}
return out;
}
/**
@@ -207,10 +263,11 @@ export class Cache<K extends string | number | symbol, T> {
* @return {Record<K, T>}
*/
map(expired?: boolean): Record<K, CachedValue<T>> {
const copy: any = deepCopy(this.store);
if(!expired) Object.keys(copy).forEach(k => {
if(copy[k]._expired) delete copy[k]
});
const copy: any = {};
for(const [k, v] of this.store.entries()) {
const val: any = v;
if(expired || !val?._expired) copy[k as any] = deepCopy<any>(val);
}
return copy;
}
@@ -223,12 +280,17 @@ export class Cache<K extends string | number | symbol, T> {
*/
set(key: K, value: T, ttl = this.options.ttl): this {
if(this.options.expiryPolicy == 'keep') delete (<any>value)._expired;
this.store[key] = value;
this.clearTimer(key);
this.store.set(key, value);
this.touchLRU(key);
this.save(key);
if(ttl) setTimeout(() => {
this.expire(key);
this.save(key);
}, (ttl || 0) * 1000);
if(ttl) {
const t = setTimeout(() => {
this.expire(key);
this.save(key);
}, (ttl || 0) * 1000);
this.timers.set(key, t);
}
return this;
}
@@ -236,5 +298,5 @@ export class Cache<K extends string | number | symbol, T> {
* Get all cached items
* @return {T[]} Array of items
*/
values = this.all();
values = this.all
}