node.js - Return the largest value for each type within the same query -

i have schema lifts hold 2 key pieces of information - lift (bench, deadlift, squat, etc) weight (for weight lifted).

what know how go finding largest weight lifted each lift.

i can populate array lifts given user, not know how further reduce results down, can done in same query?

var lift = new schema({     uid: { type: string },     lift: { type: string },     weight: { type: number },     measurement: { type: string },     date: { type: date, default: date.now },     gear: [{type: string}] }); 

i using mongoose node.js , express.

something (on mongodb shell aggregation framework):

db.so.aggregate( [     { $group: {         _id: '$lift',         max: { $max: '$weight' }     } } ] ); 

with following input (abridged):

db.so.insert( { lift: 'bench', weight: 80 } ); db.so.insert( { lift: 'bench', weight: 40 } ); db.so.insert( { lift: 'bench', weight: 76 } ); db.so.insert( { lift: 'squat', weight: 76 } ); db.so.insert( { lift: 'squat', weight: 72 } ); db.so.insert( { lift: 'squat', weight: 172 } ); db.so.insert( { lift: 'deadlift', weight: 142 } ); 

this outputs:

{     "result" : [         {             "_id" : "deadlift",             "max" : 142         },         {             "_id" : "squat",             "max" : 172         },         {             "_id" : "bench",             "max" : 80         }     ],     "ok" : 1 } 

in node.js, you'd change:

db.so.aggregate( [     { $group: {         _id: '$lift',         max: { $max: '$weight' }     } } ] ); 

with:

collection.aggregate( [     { $group: {         _id: '$lift',         max: { $max: '$weight' }     } } ], function(err, result) {  } );