virtualenv like setup for node.js projects

gistfile1.txt

Assume that a node project exists in /home/alan/autolabjs with the corresponding dependencies in 
/home/alan/autolabjs/node_modules. Let's also say we have mocha dependency installed in node_modules.

Now, a regular way to use the installed dependencies is to execute mocha is as follows.
$cd /home/alan/autolabjs/
$./node_modules/.bin/mocha <rest of the command>

Since the soft links to all the installed node modules are available in 
/home/alan/autolabjs/node_modules/.bin directory, we can add this directory to the PATH variable
to utilise all the installed dependencies like regular shell utilities.

$export PATH="/home/alan/autolabjs/node_modules/.bin":$PATH

Now to execute mocha, we only need to say
$mocha <rest of the command>