la-visitor/scripts/settings/option.js

import { types } from "assets/types.js";

class option {
    #name;
    #options;
    #default;

    constructor(name) {
        types.check_string(name);

        name = name.trim();

        if (name.length === 0) {
            throw new TypeError("Name can not be blank.");
        }

        this.#name = name;
        this.#default = undefined;
        this.#options = new Set();
    }

    #sanitize_option(option) {
        types.check_string(option);

        option = option.trim();

        if (option.length === 0) {
            throw new TypeError("Option could not be blank.");
        }

        return option;
    }

    set _default(option) {
        option = this.#sanitize_option(option);
        
        this.#default = option;
        this.#options.add(option);
    }

    _add_option(option) {
        this.#options.add(this.#sanitize_option(option));
    }

    get options() {
        return Array.from(this.#options.values());
    }

    get default() {
        if (this.#default === undefined) {
            throw new ReferenceError("Default option is not setup yet.");
        }

        return this.#default;
    }

    select(option) {
        if (!this.#options.has(option)) {
            throw new Error("Setting has not option \"" + option + "\".");
        }

        if (this.default === option) {
            localStorage.removeItem(this.#name);
            return;
        }

        localStorage.setItem(this.#name, option);
    }
    
    get selected() {
        const read = localStorage.getItem(this.#name);

        if (read === null) {
            return this.default;
        }

        if (!this.#options.has(read)) {
            return this.default;
        }

        return read;
    }
}

export { option };