jsSingeltoneDraft

<script>
        'use strict'
        {

            let BaseInstance;

            class Base {
                constructor(id) {
                    // this = new Object();
                    // this = {};
                    this._id = id;

                    if (!BaseInstance) {
                        BaseInstance = this;
                    }
                    return BaseInstance;
                }
                getId() { return this._id };
                print() { console.log(`Hello, from Base class with id: ${this._id}`); };
            }
        }

        {
            let bc1 = new Base(1);
            let bc2 = new Base(2);
            let bc3 = new Base(3);

            bc1.print();
            bc2.print();
            bc3.print();

            console.log(`Are objects differ? : ${bc1 != bc2}`);
            console.log(`Are objects differ? : ${bc2 != bc3}`);
        }
    </script>