proxy-storage

Proxy wrapper around GM storage API, with support for nested object by proxy.

Ten skrypt nie powinien być instalowany bezpośrednio. Jest to biblioteka dla innych skyptów do włączenia dyrektywą meta // @require https://update.greasyfork.org/scripts/488549/1335042/proxy-storage.js 

// ==UserScript==
// @name         proxy-storage
// @description  Proxy wrapper around GM storage API, with support for nested object by proxy.
// @version      0.0.1
// @namespace    owowed.moe
// @author       owowed <island@owowed.moe>
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_deleteValue
// @grant        GM_listValues
// @license      LGPL-3.0
// ==/UserScript==

function createGmProxyStorage({
    get = GM_getValue,
    set = GM_setValue,
    deleteValue = GM_deleteValue,
    list = GM_listValues
} = {}) {
    const storage = { get, set, deleteValue, list };
    return new Proxy({}, {
        get(target, prop, receiver) {
            const value = storage.get(prop);
            if (isObjectOrArray(value)) {
                return makeNestedTargetProxy(value, prop, storage.set);
            }
            else {
                return value;
            }
        },
        set(target, prop, newValue, receiver) {
            storage.set(prop, newValue);
            return true;
        },
        deleteProperty(target, prop) {
            storage.deleteValue(prop);
            return true;
        },
        ownKeys(target) {
            return storage.list();
        },
        has(target, prop) {
            return this.ownKeys(target).includes(prop);
        },
        getOwnPropertyDescriptor(target, prop) {
            if (this.has(target, prop)) {
                return {
                    enumerable: true,
                    configurable: true,
                    writable: false,
                    value: this.get(target, prop)
                };
            }
        },
    });
}

function isObjectOrArray(value) {
    return Array.isArray(value) || (typeof value == "object" && value != null);
}

function makeNestedTargetProxy(rootTarget, rootTargetProp, setter) {
    const set = (target, prop, value) => {
        target[prop] = value;

        setter(rootTargetProp, rootTarget); /* `rootTarget` reference will always get updated */

        return value;
    };

    const get = (target, prop) => {
        const value = target[prop];

        if (isObjectOrArray(value)) {
            return new Proxy(value, { get, set });
        }

        return value;
    };

    return new Proxy(rootTarget, { get, set });
}