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propsData removed 
Overview 
The propsData option, used to pass props to the Vue instance during its creation, is removed. To pass props to the root component of a Vue 3 application, use the second argument of createApp.
2.x Syntax 
In 2.x, we were able to pass props to a Vue instance during its creation:
js
const Comp = Vue.extend({
  props: ['username'],
  template: '<div>{{ username }}</div>'
})
new Comp({
  propsData: {
    username: 'Evan'
  }
})3.x Update 
The propsData option has been removed. If you need to pass props to the root component instance during its creation, you should use the second argument of createApp:
js
const app = createApp(
  {
    props: ['username'],
    template: '<div>{{ username }}</div>'
  },
  { username: 'Evan' }
)