begin{shaded}
  begin{lstlisting}[caption=Definition of a relation object., label=list:relation-object, language=JavaScript]
var UserProjectRelation = relation
  .from(User)
  .to(Project)
  .via("member");
  end{lstlisting}
end{shaded}

lstdefinelanguage{JavaScript}{
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  ndkeywords={class, export, boolean, throw, implements, import, this, string, number, boolean},
  sensitive=false,
  comment=[l]{//},
  morecomment=[s]{/*}{*/},
  morestring=[b]',
  morestring=[b]",
  inputencoding=utf8
}

lstset{
   language=JavaScript,
   numbers=left,
   captionpos=b
}
definecolor{shadecolor}{named}{sbase03}

DeclareCaptionFormat{captionFormat}{%
  color{white}{ttfamily#1#2#3}
}
captionsetup[lstlisting]{format=captionFormat}