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Enum

Enumeration class. Each enum propertiy has the properties "ordinal", "name" and "text".

目前为 2019-11-03 提交的版本。查看 最新版本。

此脚本不应直接安装，它是一个供其他脚本使用的外部库。如果您需要使用该库，请在脚本元属性加入：// @require https://update.cn-greasyfork.org/scripts/391854/746350/Enum.js 

// ==UserScript==
// @name         Enum
// @namespace    hoehleg.userscripts.private
// @version      0.2
// @description  Enumeration class. Each enum propertiy has the properties "ordinal", "name" and "text".
// @author       Gerrit Höhle
// @grant        none
// ==/UserScript==

/* jslint esnext: true */
const Enum = (() => {
    const initializing = Symbol("initializing");

    const createEnumInstance = (enumClass, name, ordinal, text) => {
        text = (typeof text === "undefined") ? undefined : String(text);
        return Object.assign(new enumClass(initializing), {
            get ordinal() { return ordinal; },
            get name() { return name; },
            get text() { return text; },
        });
    };

    return class EnumBase {

        constructor(processIndicator) {
            if (processIndicator !== initializing) {
                throw TypeError("Instantiation of abstract enum class");
            }
        }

        valueOf() { 
            return this.ordinal; 
        }

        toString() { 
            return (typeof this.text === "undefined") ? this.name : this.text;
        }

        static init(enumDef = [], firstOrdinal = 0, ordinalSupplier = previousOrdinal => previousOrdinal + 1) {
            if (Object.isFrozen(this)) {
                throw TypeError("Reinitialization of finalized enum class");
            }

            let ordinal;
            const ordinals = [];
            for (let enumDefObj of (Array.isArray(enumDef) ? enumDef : [ enumDef ])) {
                if (typeof enumDefObj !== 'object') {
                    enumDefObj = { [enumDefObj]: undefined };

                }
                for (let [name, text] of Object.entries(enumDefObj)) {
                    ordinal = Number.parseInt((typeof ordinal === "undefined") ? firstOrdinal : ordinalSupplier(ordinal));
                    console.assert(typeof this[name] === "undefined", `duplicate enum [${name}]`);
                    console.assert(typeof this[ordinal] === "undefined", `duplicate ordinal [${ordinal}] for enum [${name}]`);

                    ordinals.push(ordinal);

                    this[name] = createEnumInstance(this, name, ordinal, text);
                    Object.defineProperty(this, ordinal, { value: this[name] });
                }
            }

            const enums = ordinals.sort().map(ordinal => this[ordinal]);
            Object.defineProperty(this, Symbol.iterator, { value: () => enums[Symbol.iterator]() });

            return Object.freeze(this);
        }
    };
})();