in-js gsettings bind/cache

gistfile1.txt

class EffectSettings {
    constructor() {
        this._values = {};
    }

    get_string(key) {
        return this._getValue(key, 'string');
    }

    get_int(key) {
        return this._getValue(key, 'int');
    }

    get_boolean(key) {
        return this._getValue(key, 'boolean');
    }

    _getValue(key, type) {
        if (!this._values.hasOwnProperty(key))
            this._bind(key, type);

        return this._values[key];
    }

    _bind(key, type) {
        if (!global.settings.list_keys().includes(key))
            throw new Error("invalid key " + key);

        // "Note that settings only emits this signal if you have read key at
        //  least once while a signal handler was already connected for key."
        global.settings.connect("changed::" + key, (src, key) => {
            this._values[key] = Gio[`_real_get_${type}`].call(global.settings, key);
        });
        this._values[key] = Gio[`_real_get_${type}`].call(global.settings, key);
    }
}