const modules = {
    _cache: {},
    _registry: {},
    require(moduleName) {
        if (this._cache[moduleName]) {
            return this._cache[moduleName];
        }
    
        if (this._registry[moduleName]) {
            const loaderFunction = this._registry[moduleName];
            this._cache[moduleName] = loaderFunction(1);
            return this._cache[moduleName];
        }
    
        return null;
    },
    register(moduleName, loaderFunction) {
        this._registry[moduleName] = loaderFunction;
        this._cache[moduleName] = loaderFunction(0);
    },
    registerLazy(moduleName, loaderFunction) {
        this._registry[moduleName] = loaderFunction;
    }
};

window.modules = modules;