+ const q = (id,delta) => Object.entries(req.query)
+ .map(([k,v]) => k == id ? `${k}=${+v+delta}` : `${k}=${v}`)
+ .join('&')
+ const p = id => `<a href=/usage?${q(id,+1)} style="background-color:#ddd;"> + </a>`
+ const m = id => `<a href=/usage?${q(id,-1)} style="background-color:#ddd;"> − </a>`
+ const d = id => `<span title=${req.query[id]}>${id} ${p(id)} ${m(id)}</span>`
+ res.send(style('usage',key)+`