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Enum

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

Fra og med 03.11.2019. Se den nyeste version.

Dette script bør ikke installeres direkte. Det er et bibliotek, som andre scripts kan inkludere med metadirektivet // @require https://update.greasyfork.org/scripts/391854/746332/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);
        }
    };
})();