Object.defineProperty()

The static method Object.defineProperty() defines a new property directly on an object, or modifies an existing property on an object, and returns the object.

const object1 = {};

Object.defineProperty(object1, 'property1', {
  value: 42,
  writable: false
});

object1.property1 = 77;
// throws an error in strict mode

console.log(object1.property1);
// expected output: 42