127 lines
2.2 KiB
JavaScript
127 lines
2.2 KiB
JavaScript
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export /*abstract */class Cache {
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/**
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* @param {string} key
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* @return {boolean}
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* @author svartoyg
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*/
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/*protected */has(key) {
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throw (new Error('not implemented'));
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}
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/**
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* @param {string} key
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* @return {any}
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* @author svartoyg
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*/
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/*protected */fetch(key) {
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throw (new Error('not implemented'));
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}
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/**
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* @param {string} key
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* @param {any} value
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* @author svartoyg
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*/
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/*protected */store(key, value) {
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throw (new Error('not implemented'));
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}
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/**
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* @param {string} key
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* @param {()=>Promise<any>} retrieve
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* @return {Promise<any>}
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* @author svartoyg
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*/
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/*public */async get(key, retrieve) {
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if (this.has(key)) {
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const value = this.fetch(key);
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return Promise.resolve(value);
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} else {
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const value = await retrieve();
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this.store(key, value);
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return Promise.resolve(value);
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}
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}
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}
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/**
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* @author svartoyg
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*/
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class CacheNone extends Cache {
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/**
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* @author svartoyg
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*/
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/*public */constructor() {
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super();
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}
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/**
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* @author svartoyg
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*/
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/*protected */has(key) {
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return false;
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}
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/**
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* @author svartoyg
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*/
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/*protected */fetch(key) {
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throw (new Error('not possible'));
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}
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/**
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* @author svartoyg
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*/
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/*protected */store(key, value) {
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}
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}
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/**
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* @author svartoyg
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*/
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export class CacheLocalstorage extends Cache {
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/**
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* @param {string} [corner] for separating the cache instance from others
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* @author svartoyg
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*/
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/*public */constructor(corner = null) {
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super();
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this.corner = corner;
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}
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/**
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* @author svartoyg
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*/
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/*private */augmentKey(key) {
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return ((this.corner === null) ? key : (this.corner + '/' + key));
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}
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/**
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* @author svartoyg
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*/
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/*protected */has(key) {
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return (window.localStorage.getItem(this.augmentKey(key)) !== null);
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}
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/**
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* @author svartoyg
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*/
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/*protected */fetch(key) {
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const valueRaw = window.localStorage.getItem(this.augmentKey(key));
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const value = JSON.parse(valueRaw);
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return value;
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}
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/**
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* @author svartoyg
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*/
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/*protected */store(key, value) {
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const valueRaw = JSON.stringify(value);
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window.localStorage.setItem(this.augmentKey(key), valueRaw);
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}
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}
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