Mastering JavaScript

Server-Side JavaScript
The geo module created earlier in this section can be rewritten in order to return a
single Geo constructor function rather than an object containing functions. We can
rewrite the geo module and its usage as follows:
var Geo = function(PI) {
this.PI = PI;
}
Geo.prototype.area = function (r) {
return this.PI * r * r;
};
Geo.prototype.circumference = function (r) {
return this.PI * this.PI * r;
};
module.exports = Geo;
Consider a config.js module:
var db_config = {
server: "0.0.0.0",
port: "3306",
user: "mysql",
password: "mysql"
};
module.exports = db_config;
If you want to access db_config from outside this module, you can use require()
to include the module and refer the object as follows:
var config = require('./config.js');
console.log(config.user);
There are three ways to organize modules:
• Using a relative path, for example, config = require('./lib/config.
js')
• Using an absolute path, for example, config = require('/nodeproject/
lib/config.js')
• Using a module search, for example, config = require('config')
The first two are self-explanatory—they allow Node to look for a module in a
particular location in the filesystem.
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