Implement the interface SugarCube uses for serializing and deserializing objects.

SugarCubeObject.js

window.SugarCubeObject =  class SugarCubeObject {
    constructor() {
        this.reviveWrapper = '(new ' + this.constructor.name + '())._init($ReviveData$)'
    }
    _init(obj) {
        Object.keys(obj).forEach(pn => {this[pn] = clone(obj[pn])});
        return this;
    }
    
    clone () {
        return (new this.constructor())._init(this);
    }

    toJSON () {
        let ownData = {};
        Object.keys(this).forEach(pn => {ownData[pn] = clone(this[pn])});
        return JSON.reviveWrapper(this.reviveWrapper, ownData)
    }
}