CODE EXAMPLE FOR JAVASCRIPT

this.$set in vue 3

VUE 2 >>>
data() {
  return {
    personObject: {
      name: 'John Doe'
    }
  }
},
methods: {
  addBio(bio) {
     this.$set(this.personObject, 'bio', bio)  // this was needed on vue 2
}

VUE 3 >>>
methods: {
  addBio(bio) {
     this.personObject['bio'] = bio   // no more this.$set in vue 3
  }
}