NodeJS Module Pattern

Question

NodeJS Module Pattern

I'm about to begin writing a new module for a system I'm developing. We use a MySQL database (so I'm using node-mysql) which contains a customers table.

What I want to achieve is:

Outside of the module I'm looking to do var C = new Customer(1) where 1 is the customer ID.
Now when I want to get something from this customer, I can do C.email or C.first_name which will simply return a value.
I also need to be able to set values back on this customer, C.email = 'example@example.com' or perhaps:

C.set('email', 'example@example.com')

What would be the best pattern to create such a model?

node.js
design-patterns
module

Answer 1

I already have something like this... Not exactly what you demanded but very close to that I have generalized the core part and here is the code..Hope this will help....

var mysql = require('mysql');
var con = mysql.createConnection({
host:"yourHostName",
user:"yourUserName",
password:"yourPassword"
});
con.query("use databaseName");
function getCustomerDetails(custId){
con.query("select * from customer where custId = "+custId,function(err,result,fields){
if(!err)
    return result;
else
    console.log(err);
});
}
function updateCustomerDetails(custId,fieldName,fieldValue){
con.query("update customer set "+fieldName+" = "+fieldValue+" where custId =       "+custId,function(err,result,fields){
    if(!err)
        return true;
    else
        console.log(err);
        return false;
});
}
exports.getCustomerDetails = getCustomerDetails;
exports.updateCustomerDetails = updateCustomerDetails;

And then suppose you saved the module as dbAccessModule.js Then you can use the functions like this

var C = require('./dbAccessModule');
result = C.getCustomerDetails(1);
console.log(result.fieldName);

var success = C.updateCustomerDetails(1,'name','sumit');         
if(success)
console.log('Table Updated successfully....');
else
// take necessary action according to your application

One thing you need to take care of is that if you are updating any field with string value then please don't forget to surround the value of fieldValue with single quotes.

If this is not what you asked for then please ignore it....

Answer 2

I recently created two database modules you might be interested in checking out to see if they fit your needs - an ORM: http://bookshelfjs.org and Query Builder: http://knexjs.org

The ORM is based off of the design patterns of Backbone.js

So, you'd be able to do something like this:

// Create the base customer object
var Customer = Bookshelf.Model.extend({
  tableName: 'customers'
});

// Create a new customer instance with an id of 1, fetch it, and then
// act on the result model 'customer'.
new Customer({id: 1}).fetch().then(function(customer) {
  console.log(customer.get('name'))
  customer.set('email', 'email@example.com')
  return customer.save();
});

You could also extend the base Customer class to enable a shortened syntax, similar to what you're looking for:

// Create the base customer object, with a static findOne method.
var Customer = Bookshelf.Model.extend({
  tableName: 'customers'
}, {
  find: function(id) {
    return new this({id: id}).fetch();
  }
});

Customer.find(1).then(function(C) {
   console.log(C.get('name'))
   C.set('email', 'email@example.com')
});