Non-writeable properties

February 15, 2022

A non-writable property cannot be changed with an assignment operator (=, *=, **=, /=, +=, -=)

To define a non-writeable property on an object use Object.defineProperty() and set writable to false:

var obj = {}
// writable is also false by default
Object.defineProperty(obj, 'a', { value: 2, writable: false });