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PrivateProperty

Weakly references a value to a specified object. May be used to create private fields.

此脚本不应直接安装。它是供其他脚本使用的外部库，要使用该库请加入元指令 // @require https://update.cn-greasyfork.org/scripts/391608/744693/PrivateProperty.js 

  1. // ==UserScript==
  2. // @name         PrivateProperty
  3. // @namespace    hoehleg.userscripts.private
  4. // @version      0.2
  5. // @description  Weakly references a value to a specified object. May be used to create private fields.
  6. // @author       Gerrit Höhle
  7. // @grant        none
  8. // ==/UserScript==
  9.  
  10. /* jshint esversion: 6 */
  11. const PrivateProperty = (() => {
  12.     let prototypeFunctions;
  13.  
  14.     class PrivateProperty {
  15.  
  16.         constructor(initialValue) {
  17.             this._weakReferences = new WeakMap();
  18.             this._initialValue = initialValue;
  19.         }
  20.  
  21.         init(object, initialValueSpecific = this._initialValue) {
  22.             const value = (typeof initialValueSpecific === "function") ? initialValueSpecific() : initialValueSpecific;
  23.             this._weakReferences.delete(object);
  24.             this._weakReferences.set(object, {
  25.                 initialValue: initialValueSpecific,
  26.                 value: value
  27.             });
  28.             return this;
  29.         }
  30.  
  31.         has(object) {
  32.             return this._weakReferences.has(object);
  33.         }
  34.  
  35.         get(object) {
  36.             const data = this._weakReferences.get(object);
  37.             if (data) {
  38.                 return data.value;
  39.             }
  40.         }
  41.  
  42.         set(object, value) {
  43.             const data = this._weakReferences.get(object) || {
  44.                 initialValue: this._initialValue
  45.             };
  46.             data.value = value;
  47.             this._weakReferences.set(object, data);
  48.         }
  49.  
  50.         getInitialValue(object) {
  51.             const data = this._weakReferences.get(object);
  52.             return data ? data.initialValue : this._initialValue;
  53.         }
  54.  
  55.         getOrCompute(object, fnc) {
  56.             let data = this._weakReferences.get(object);
  57.             if (!data) {
  58.                 data = {
  59.                     initialValue: this._initialValue,
  60.                     value: fnc()
  61.                 };
  62.                 this._weakReferences.set(object, data);
  63.             }
  64.             return data.value;
  65.         }
  66.  
  67.         for(object) {
  68.             const bound = prototypeFunctions.map(([propName, fnc]) => ({ [propName]: fnc.bind(this, object) }));
  69.             return Object.assign({}, ...bound);
  70.         }
  71.     }
  72.  
  73.     prototypeFunctions = Object.getOwnPropertyNames(PrivateProperty.prototype)
  74.         .filter(propName => typeof PrivateProperty.prototype[propName] === "function")
  75.         .filter(propName => propName !== "constructor")
  76.         .filter(propName => propName !== "for")
  77.         .map(propName => ([ [propName], PrivateProperty.prototype[propName] ]));
  78.  
  79.     return PrivateProperty;
  80. })();