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PrivateProperty

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

Ce script ne devrait pas être installé directement. C'est une librairie créée pour d'autres scripts. Elle doit être inclus avec la commande // @require https://update.greasyfork.org/scripts/391608/744693/PrivateProperty.js 

// ==UserScript==
// @name         PrivateProperty
// @namespace    hoehleg.userscripts.private
// @version      0.2
// @description  Weakly references a value to a specified object. May be used to create private fields.
// @author       Gerrit Höhle
// @grant        none
// ==/UserScript==

/* jshint esversion: 6 */
const PrivateProperty = (() => {
    let prototypeFunctions;

    class PrivateProperty {

        constructor(initialValue) {
            this._weakReferences = new WeakMap();
            this._initialValue = initialValue;
        }

        init(object, initialValueSpecific = this._initialValue) {
            const value = (typeof initialValueSpecific === "function") ? initialValueSpecific() : initialValueSpecific;
            this._weakReferences.delete(object);
            this._weakReferences.set(object, {
                initialValue: initialValueSpecific,
                value: value
            });
            return this;
        }

        has(object) {
            return this._weakReferences.has(object);
        }

        get(object) {
            const data = this._weakReferences.get(object);
            if (data) {
                return data.value;
            }
        }

        set(object, value) {
            const data = this._weakReferences.get(object) || {
                initialValue: this._initialValue
            };
            data.value = value;
            this._weakReferences.set(object, data);
        }

        getInitialValue(object) {
            const data = this._weakReferences.get(object);
            return data ? data.initialValue : this._initialValue;
        }

        getOrCompute(object, fnc) {
            let data = this._weakReferences.get(object);
            if (!data) {
                data = {
                    initialValue: this._initialValue,
                    value: fnc()
                };
                this._weakReferences.set(object, data);
            }
            return data.value;
        }

        for(object) {
            const bound = prototypeFunctions.map(([propName, fnc]) => ({ [propName]: fnc.bind(this, object) }));
            return Object.assign({}, ...bound);
        }
    }

    prototypeFunctions = Object.getOwnPropertyNames(PrivateProperty.prototype)
        .filter(propName => typeof PrivateProperty.prototype[propName] === "function")
        .filter(propName => propName !== "constructor")
        .filter(propName => propName !== "for")
        .map(propName => ([ [propName], PrivateProperty.prototype[propName] ]));

    return PrivateProperty;
})();