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Deep Object Mutability

Consider the following object representing a user, Joe, and his dog, Buttercup. We use Object.freeze to preserve our object and then attempt to mutate Buttercup's name. What gets logged?

const user = {
  name: 'Joe',
  age: 25,
  pet: {
    type: 'dog',
    name: 'Buttercup'


user.pet.name = 'Daffodil';


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