'use strict'; const containerValue = Symbol('containerValue'); class Container { constructor(value) { Object.defineProperty(this, containerValue, { configurable: false, enumerable: false, writable: false, value, }); } getValue() { return this[containerValue]; } } // Usage const container1 = new Container(150); console.dir({ container1 }); console.log('container1.getValue() =', container1.getValue()); const person = { name: 'Marcus', born: 121, city: 'Roma' }; const container2 = new Container({ person }); console.dir({ container2 }); console.log('container2.getValue() =', container2.getValue());