Javascript Constants
In JavaScript, a constant is a variable whose value cannot be changed after it has been assigned. Constants are declared using the const keyword. For example:
const x = 10;
Once the value of x has been set to 10, it cannot be changed. Attempting to do so will result in a TypeError. This makes constants useful for storing values that should never change during the lifetime of a program, such as mathematical constants or configuration values.
It is important to note that while the value of a constant cannot be changed, if the constant references an object, the properties of that object can still be modified. For example:
const obj = {}; obj.x = 10; console.log(obj.x); // outputs 10
Here, we declared a constant obj that references an object. Even though obj is a constant, we can still add or modify properties on the object that it references.