Mutability And Reference VS Privative Types in JavaScript Mutability And Reference VS Privative Types in JavaScript Mutability && Primitive && Reference Examples Mutability And Reference VS Privative Types in JavaScript Mutability && Primitive && Reference Examples Mutability In JavaScript, String values are immutable, which means that they cannot be altered once created. For example, the following code: var myStr = "Bob"; myStr[0] = "J";