107 lines
2.2 KiB
TypeScript
107 lines
2.2 KiB
TypeScript
/**
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* Map of data which tracks whether it is a complete collection & offers optional expiry of cached values
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*/
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export class Cache<K, T> {
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private store: any = {};
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/** Whether cache is complete */
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complete = false;
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/**
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* Create new cache
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*
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* @param {keyof T} key Default property to use as primary key
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* @param {number} ttl Default expiry in milliseconds
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*/
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constructor(public readonly key: keyof T, public ttl?: number) { }
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private getKey(value: T): K {
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return <K>value[this.key];
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}
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/**
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* Get all cached items
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*
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* @return {T[]} Array of items
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*/
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all(): T[] {
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return Object.values(this.store);
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}
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/**
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* Add a new item to the cache. Like set, but finds key automatically
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*
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* @param {T} value Item to add to cache
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* @param {number | undefined} ttl Override default expiry
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* @return {this}
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*/
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add(value: T, ttl = this.ttl): this {
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const key = this.getKey(value);
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this.set(key, value, ttl);
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return this;
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}
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/**
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* Add several rows to the cache
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*
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* @param {T[]} rows Several items that will be cached using the default key
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* @param complete Mark cache as complete & reliable, defaults to true
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* @return {this}
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*/
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addAll(rows: T[], complete = true): this {
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rows.forEach(r => this.add(r));
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this.complete = complete;
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return this;
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}
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/**
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* Delete an item from the cache
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*
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* @param {K} key Item's primary key
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*/
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delete(key: K) {
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delete this.store[key];
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}
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/**
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* Return cache as an array of key-value pairs
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* @return {[K, T][]} Key-value pairs array
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*/
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entries(): [K, T][] {
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return <[K, T][]>Object.entries(this.store);
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}
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/**
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* Get a list of cached keys
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*
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* @return {K[]} Array of keys
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*/
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keys(): K[] {
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return <K[]>Object.keys(this.store);
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}
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/**
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* Add an item to the cache manually specifying the key
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*
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* @param {K} key Key item will be cached under
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* @param {T} value Item to cache
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* @param {number | undefined} ttl Override default expiry
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* @return {this}
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*/
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set(key: K, value: T, ttl = this.ttl): this {
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this.store[key] = value;
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if(ttl) setTimeout(() => {
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this.complete = false;
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this.delete(key);
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}, ttl);
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return this;
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}
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/**
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* Get all cached items
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*
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* @return {T[]} Array of items
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*/
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values = this.all();
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}
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