ReQL: For a field get in one query the count, min, max and sample entries

gistfile1.js

r.db('mydb').table('disk').withFields('glist').groupedMapReduce(
  function(x) { return x },
  function(x) { return 1 },
  function(x,y) { return 1 }
  )
  .map(function (x) { return x('group')('glist') })
  .reduce(function(x,y) { return
    {
      count: x('count').add(1),
      val: x('val').union([y]).sample(10),
      min: r.branch(x('min'), r.branch(x('min').lt(y), x('min'), y), y),
      max: r.branch(x('max'), r.branch(x('max').gt(y), x('max'), y), y)
  }},
    {count: 0, val: [], min: null, max:null})