[REMINDER-6] Object.assign/setPrototypeOf

ASSIGN

this method copies all the enumerable own properties of one or more objects into another

It mean's values are cloned, and objects references are copied live for vuejs < 3 (I didn't check for vue 3 reactivity but it's different normally).

example:

const original = {
  name: 'Fiesta',
  car: {
    color: 'blue'
  }
}

const copied = Object.assign({}, original)

original.name = 'Focus'
original.car.color = 'yellow'

copied.name //Fiesta
copied.car.color //yellow

Name doesn't change everywhere because it's not an object. For car yes and no matter if you change the copied object or the orignal one.

IMPORTANT: Spread operator does the same because it uses Object.assign behind the scene

const original = {
  name: 'Fiesta',
  car: {
    color: 'blue'
  }
}

const copied = {...original}

original.name = 'Focus'
original.car.color = 'yellow'

copied.name //Fiesta
copied.car.color //yellow

setPrototypeOf

Copy all proto values from an object to another one.

const animal = {
  isAnimal: true
}
const mammal = {
  isMammal: true
}

// mammal.__proto__ = animal
Object.setPrototypeOf(animal, mammal). // Same as doing before