
\setuphead
  [chapter]
  [style=\tfd,
   command=\MyHeadCommand]

\define[2]\MyHeadCommand%
  {\bTABLE[width=broad,offset=0pt,frame=off]
    \setupTABLE[column][first][width=1.5em]
    \bTR \bTD #1 \eTD \bTD #2 \eTD \eTR
    \bTR \bTD    \eTD
      \bTD[style=\tfc\setupinterlinespace] \structureuservariable{subtitle} \eTD
    \eTR
   \eTABLE}

\setuplist
  [chapter]
  [alternative=command,command=\MyListCommand]

\define[3]\MyListCommand%
  {\bTABLE[offset=0pt,frame=off,distance=.5em,width=broad]
     \bTR
       \bTD[width=1.5em] #1 \eTD
       \bTD              #2
         \doifsomething % test if a subtitle is set
           {\structurelistuservariable{subtitle}}
           {– \structurelistuservariable{subtitle}}
       \eTD
       \bTD[width=1.5em,align={left,low}] #3 \eTD
     \eTR
   \eTABLE}


\starttext

\placelist[chapter]

\startchapter
  [title=Title]
  [subtitle=Subtitle]
  
  \input tufte
\stopchapter

\startchapter
  [title=A \dorecurse{15}{very }long Title]
  [subtitle=A \dorecurse{15}{very }long Subtitle]
  
  \input tufte
\stopchapter

\stoptext

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