function hasValue () {
  const value = this.proxy
  if (
    (this.classification === 'box' && this.isGrouped) ||
    (this.classification === 'select' && has(this.filteredAttributes, 'multiple'))
  ) {
    return Array.isArray(value) ? value.some(v => v === this.value) : this.value === value
  }
  return !isEmpty(value)
}
Determines if the current input has a value or not. To do this we need to
check for various falsey values. But we cannot assume that all falsey values
mean an empty or unselected field (for example 0) and we cant assume that
all truthy values are empty like [] or {}.