const

The const keyword only makes the binding immutable, that is, you can only assign a value to a const variable once. In JavaScript, only Primitives values are immutable. However, non-primitive values can still be mutated.

const MY_FIRST_CONSTANT = 10;

// Can not be re-assigned.
MY_FIRST_CONSTANT = 20;
// => TypeError: Assignment to constant variable.

const MY_MUTABLE_VALUE_CONSTANT = { food: 'apple' };

// This is possible
MY_MUTABLE_VALUE_CONSTANT.food = 'pear';

MY_MUTABLE_VALUE_CONSTANT;
// => { food: "pear" }

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Backlinks

• Variable Assignment