Example of using computed

test.js

// When input it blank, this returns the error

// INPUT
<fg-input
  v-model="editCustomer.firstName"
  placeholder="First Name"
  label="First Name"
  name="firstName"
  :error="handleErrors"
></fg-input>

// computed
handleErrors(){
      if(!this.editCustomer.firstName){
        return this.errorMessages.blankError
      }
    },
      
// errors in data
 errorMessages: {
    blankError: 'Input cannot be blank',
    nonNumericError: 'Input must be numeric',
    invalidEmail: 'Invalid email address format'
  },