sails.js - How to update a model with an array property in sailsjs waterline -

i have model friends property type of array.

var bcrypt = require('bcrypt');  module.exports = {    attributes: {     id : {         type: 'integer',         autoincrement: true     },     username : {       type : 'string',       required : true,       unique : true     },     email : 'string',     firstname : 'string',     lastname : 'string',     password : 'string',     friends : 'array'   },    beforecreate: function(values, next) {     bcrypt.hash(values.password, 10, function(err, hash) {       if (err) {         return next(err);       }       values.password = hash;       next();     });   } }; 

this route method.

addfriend : function (req, res) {     user.findone({username : req.session.user.username}).exec(function (err, user) {         if(!user.friends)user.friends = [];         user.friends.push(req.param('friend'));         user.save(function (err) {             console.log(err);         });     }); } 

i've used user.update(criteria, data) update model, can't update model @ using .save(), doing ...

addfriend : function (req, res) {     user.findone({username : req.session.user.username}).exec(function (err, user) {         user.firstname = 'nate';         user.save(function (err) {             console.log(err);         });     }); } 

is there other way save without doing model.update, or how can push array using method. i've looked everywhere why can't solve this, , i've used many orm's in node waterline docs show using save on model after finding.

this error on save method

[error: error updating record.] 

you combine .findone , .update.

addfriend : function (req, res) {     user.findone({username : req.session.user.username}).exec(function (err, user) {         var friends = user.friends ? user.friends : [];         friends.push(req.param('friend'));         user.update({username: req.session.user.username}, {friends: newfriends})             .exec(function(err, updateduser) {                 return res.json(updateduser);             });     }); }