JavaScript read-only objects

We can use the Object.freeze(object) method to make an object and its property values read-only:

// make an object
const myObject = { 
  myProp1: 2, 
  myProp2: "my value" 
}

// make the object ready-only
Object.freeze(myObject)

// try to change the object's property value
myObject.myProp1 = 3

// hint: you can't
console.log(myObject.myProp1)
// 2

However, if a property contains a nested object, then the properties of the nested object can still change:

const myObject = { 
  myProp1: 2, 
  myProp2: { 
    myNestedProp: "my value" 
  }
}

Object.freeze(myObject);

myObject.myProp2.myNestedProp = "your value"

console.log(myObject.myProp2.myNestedProp)
// "your value"