How to correctly pass PROPS to VUE.js?

Question

JavaScript

This code throws an error. That the variable whichScreen is not defined. Help me please

export default {
    props:{
        elem:{
            type:Object,
            required: true,  
                      
        },whichScreen:whichScreen
    },

Answer 1

whichScreen:whichScreen and what is it in general?)

elem:{
            type:Object,
            required: true,  
                      
        },
whichScreen: {
описание
}

Answer 2

First, for objects, a key must be defined in which the function returns an empty object (or not empty). In your case, you need to decide what type whichScreen will have, judging by the naming, this is a string / numberdefault: () => ({})

props:{
        elem:{
            type:Object,
            default: () => ({}),
            required: true,      
        },
        whichScreen: {
             type: [String, Number]
             // Остальные параметры по ситуации.
         }
    },