Create your configuration files.

Place this at the top of your javascript file:

var config = require('config');

Or load a specific configuration context:

var config = require('config').get('Customer');

The preferred method of accessing configurations is through get():

var dbHost = config.get('dbConfig.host');

This gives you a fail-fast system if (when?) someone screws up your configuration files - it's more common than you'd think. It will also make the configuration object immutable during the first call to get().

If a configuration file does not contain a value for a given property, get() will throw an exception. Note that null is an acceptable value, and will not throw an exception when it would be returned by get(). Get will also throw an exception if the parameter passed in to get is null or undefined.

Additionally, setting config values explicitly to undefined is a helpful way to ensure that they must be defined by a later configuration file.

The alternative is to attain the value directly:

var dbHost = config.dbConfig.host;

This doesn't give you protection from typos and configuration file problems, or immutability. But it is supported for backward compatibility.

If you want to see if a config value exists, use the has() method

if (config.has('dbConfig')) {
  ...
}

This can be done as an alternative to wrapping your get() around a try/catch block. has() will not throw exceptions, and will return true if and only if the configuration file has a defined value for the provided key. Note that null is a defined value.

has() will not throw an exception if the parameter passed is null or undefined but will simply return false.