gistfile1.js

//map:
function(doc) {
  if(doc.type == "document") {
    emit(doc._id, doc);
  }
  else if(doc.type == "version") {
    emit(doc.document_id, 1);
  }
}

//reduce:
function(keys, values) {
  var version_count = 0;
  for(var i=0; i<values.length; i++) {
    switch (typeof values[i]) {
      case "number":
      version_count += values[i];
      case "object":
      if (values[i]._id) {
        result = values[i];
      }
    }
  }
  result.version_count = version_count;
  return result;
}