{{- $author := site.Params.footer.copyright.author }}
{{- $yearStart := string site.Params.footer.copyright.yearStart }}
{{- $yearEnd := string (default (now.Format "2006") site.Params.footer.copyright.yearEnd) }}
{{- $yearSpan := "" }}
{{- if not $yearStart }}
  {{- /* Use $yearEnd if $yearStart doesn't exist */ -}}
  {{- $yearSpan = $yearEnd }}
{{- else if eq $yearStart $yearEnd }}
  {{- $yearSpan = $yearEnd }}
{{- else }}
  {{- $yearSpan = printf "%s-%s" $yearStart $yearEnd }}
{{- end -}}
<p class="footer__copyright-notice">&copy; {{ $yearSpan }} {{ $author }}</p>