{{- $date := .Date -}}
{{- with .Params.dateFormat -}}
  {{- $date | time.Format . -}}
{{- else -}}
  {{- with .Site.Params.dateFormat -}}
    {{- $date | time.Format . -}}
  {{- else -}}
    {{- $date | time.Format "2006-01-02" -}}
  {{- end -}}
{{- end -}}