node.js - forEach in mongoDB array not working -

i have mongodb model like:

data = {    dataid: string,    myarray:[] } 

i need iterate through myarray

in api writing this

data.findone({dataid: '1234567890'}, function(err, data){    data.myarray.foreach(function(tomatch, index){        data.myarray[index].key = value;    });     data.save(function(err, data){         if (err) {             return res.status(500).send(err);         }         return res.status(200).send(data)    }) }); 

but data not getting saved because nodejs executes data.save before end of foreach loop

i use cursor iterate on mongodb find() function, how can iterate on array in mongodb document, wait complete execution , call data.save

mongodb find returns array in case data array , data.myarray undefined can't execute data save too