{{- $pages := where .Site.RegularPages "Type" "in" .Site.Params.mainSections -}}
{{- $result := slice -}}

{{- range $pages -}}
    {{- $data := dict 
        "title" .Title
        "content" (.Plain)
        "id" .File.UniqueID
    -}}
    {{- $result = $result | append $data -}}
{{- end -}}

{{ jsonify $result }}