How to export properly in node.js?

Question

I'm running some issues with my node application after upgrading to Express 3.0. So, since I'm rewriting it, I was trying to follow the style of routes/index.js because it looks clean.

So, in my main app.js I have some variables such as:

var calls = 0;
var agents = [];

And also use the node-mysql module. However, the routes definition doesn't have app.js scope but their own scope so calls and agents aren't visible.

How should I make them visible?

For mysql I tried something like:

// libraries/mysql.js
mysql = require('mysql');
var mysql_conf = {
    host: myhost,
    user: myuser,
    password: mypass,
    database: mydb
};
var mysql_client = mysql.createClient(mysql_conf);

exports.mysql_client;

//Later in routes/index.js
mysql_client = require('../helpers/mysql.js');

But it seems not to work as it says TypeError: Object #<Object> has no method 'query'

Any hints please?

score 2 · Accepted Answer · answered Jul 24 '12 at 12:54

2

The line

exports.mysql_client;

Does not actually assign anything to the mysql_client property of exports. It accesses a property, and immediately discards the value. You need to do something like this:

var mysql_client = mysql.createClient(mysql_conf);
exports.mysql_client = mysql_client;

// or simply

exports.mysql_client = mysql.createClient(mysql_conf);

answered Jul 24 '12 at 12:54

Matt Ball

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I would also write `module.exports = mysql.createClient(mysql_conf);` Notice the `module`. Just to be safe. – rdrey Jul 24 '12 at 13:41
also: `var mysql_client = module.exports.client = ...` to have a nice local variable. – LoG Jul 24 '12 at 14:25
That's nice and what about the variables? – Antonio Laguna Jul 24 '12 at 15:29
1

@AntonioLaguna http://stackoverflow.com/q/4140661/139010 and http://stackoverflow.com/q/10306185/139010 – Matt Ball Jul 24 '12 at 15:45

How to export properly in node.js?

1 Answers1