mapreduce.js

"most_recent_profile": {
   "map": "function (doc) {\n  
        if (doc.type === 'personal_data') {\n
          emit(doc._id, doc);\n  
        }\n}",
   "reduce": "function (key, values, rereduce) {\n  
      var r = values[0];\n  
      for (var i = 1; i < values.length; i += 1) {\n
        if (r.timestamp < values[i].timestamp) r = values[i];\n
      }\n  
      return r;\n
    }"
}