[Vue warn] Error in render “TypeError variable is undefined”

To fix this we need to add a check simply using v-if.

v-if="userData.name.length>0"

Here notice one thing if you are checking userData.name then you should define it as

export default {
    data() {
        return {
            userData: {
                name:''
            },
        }
   }
}

If you have userData only then do like this

v-if="userData != ''"

And Define like this

export default {
    data() {
        return {
            userData:''
        }
   }
}

Thats it, Hope this solves the issue