In other programming languages, it's "by value" vs. "by reference."
One of the most confusing parts of dealing with immutability in JavaScript is understanding the array methods. "Officially", some of them are mutating, e.g., `.sort()`, while others create and return a copy, e.g., `.slice()`.
One of the most confusing parts of dealing with immutability in JavaScript is understanding the array methods. "Officially", some of them are mutating, e.g., `.sort()`, while others create and return a copy, e.g., `.slice()`.
It makes the 10-day rumor more convincing though.