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SimpleCache

A Map extended as a Cache. Optional KeyExtractor - Function, optional ValueTransformer - Functions, as well as an optional validityPeriod after which an entry is automatically going to be removed.

This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greatest.deepsurf.us/scripts/405143/815223/SimpleCache.js 

  1. // ==UserScript==
  2. // @name         SimpleCache
  3. // @namespace    hoehleg.userscripts.private
  4. // @version      0.1
  5. // @description  A Map extended as a Cache. Optional KeyExtractor - Function, optional ValueTransformer - Functions, as well as an optional validityPeriod after which an entry is automatically going to be removed.
  6. // @author       Gerrit Höhle
  7. //
  8. // @grant        none
  9. //
  10. // @require      https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js
  11. // ==/UserScript==
  12.  
  13. /* jshint esnext: true */
  14. /* globals $, jQuery */
  15. const SimpleCache = (() => {
  16.     const cloneObject = (obj) => {
  17.         if (typeof obj !== 'object' && typeof obj !== 'function' || obj === null) {
  18.             return obj;
  19.         }
  20.         return jQuery.extend(true, {}, obj);
  21.     };
  22.  
  23.     return class SimpleCache extends Map {
  24.         constructor({ keyExtractor = k => k, setValueTransformer = v => cloneObject(v), getValueTransformer = v => cloneObject(v) } = {}) {
  25.             super();
  26.             Object.assign(this, { keyExtractor, setValueTransformer, getValueTransformer });
  27.         }
  28.  
  29.         get(key) {
  30.             const finalKey = this.keyExtractor(key);
  31.             return this.getValueTransformer(super.get(finalKey));
  32.         }
  33.  
  34.         set(key, value, validityPeriodMs = 0) {
  35.             const finalKey = this.keyExtractor(key);
  36.             super.set(finalKey, this.setValueTransformer(value));
  37.  
  38.             if (validityPeriodMs > 0) {
  39.                 setTimeout(() => this.delete(finalKey), validityPeriodMs);
  40.             }
  41.             return this;
  42.         }
  43.  
  44.         has(key) {
  45.             return super.has(this.keyExtractor(key));
  46.         }
  47.  
  48.         delete(key) {
  49.             return super.delete(this.keyExtractor(key));
  50.         }
  51.     };
  52. })();