This bit of code I understand. We make a copy of A and call it C. When A is changed C stays the same
var A = 1;
var C = A;
console.log(C); // 1
A++;
console.
Console.log() is passed a reference to the object, so the value in the Console changes as the object changes. To avoid that you can:
console.log(JSON.parse(JSON.stringify(c)))
MDN warns:
Please be warned that if you log objects in the latest versions of Chrome and Firefox what you get logged on the console is a reference to the object, which is not necessarily the 'value' of the object at the moment in time you call
console.log(), but it is the value of the object at the moment you open the console.