To make an object read only or immutable you can use the Object.freeze() method.
Consider this object,
const Car = {
name: "Audi",
year: "2020",
};
We don't want any more properties to be added to this Car object.
Let's use the Object.freeze() method to achieve this.
const Car = {
name: "Audi",
year: "2020",
};
// make car object immutable
Object.freeze(Car);
Now if you try to add or change any properties in the Car object, it will throw an error in strict mode.
const Car = {
name: "Audi",
year: "2020",
};
// make car object immutable
Object.freeze(Car);
// try to add a new property
Car.engineType = "BS-VI"; // error in strict mode
- The
Object.freeze()method accepts the object to make it immutable as the parameter. - The method returns the same object which is passed into it.
- Cannot add or modify any properties and methods after calling the method.
- It also restricts any modification to the prototype.