Does a const variable make the value immutable in JavaScript?

Question

Accepted Answer

No, const does not make the value immutable.

const only makes the variable itself immutable, not the value it holds.
For objects and arrays, const prevents reassignment but allows mutation of properties or elements.
To make a value truly immutable, you can use Object.freeze() or other techniques.

Accepted Answer

Declaring a variable with the const keyword makes the reference to the variable immutable, but not the value it holds. This means that you can't reassign the variable to a different value, but you can still change the properties of an object or elements of an array that are stored in the constant variable.

For example:

const obj = {name: 'John'};
obj.name = 'Jane';  // this is allowed and the object can be changed

obj = {name: 'Jane'}; error

Top OodlesTechnologies React Developer interview questions & answers

Popular interview questions of React Developer