Write a program that finds the document with the highest recorded temperature for each state, and adds a "month_high" field for that document, setting its value to true.

hw2-2.js

// Write a program that finds the document with the highest
// recorded temperature for each state, and adds a "month_high" 
// field for that document, setting its value to true.

var MongoClient = require('mongodb').MongoClient;

MongoClient.connect('mongodb://localhost:27017/weather', function(err, db) {
    if(err) throw err;

    var cursor = db.collection('data').find({});
    cursor.sort([ ['State', 1], ['Temperature', -1] ]);	

		var state = null;

    cursor.each(function(err, doc) {
        if(err) throw err;

        if(doc == null) {
            return db.close();
        }

        if (state != doc.State) {	
        	state = doc.State;
        	update_weather(doc);
        }

    });

    function update_weather(doc) {
    	var query = {};	
  		
  		query['_id'] = doc['_id'];
  		doc['month_high'] = true;

    	db.collection('data').update(query, doc, function(err, updated) {

        if(err) throw err;

        console.dir("Successfully updated " + updated + " document!");

        return db.close();
    	});	
    }

});

we got an error while running above program-- mongo Error connection closed by application