title: Why should i create node_modules folder for nodejs dependencies for each expressjs app
body: <p>I really don't get it. When i run npm install on the main folder, why does it have to download all the dependencies in the node_modules and why does this need to be done for each single project? In Sinatra(Ruby microframework), I never had to do this and it is easy to use the gems that are installed globally without having to download and save each one of them into the project folder again. </p>
  
  <p>I read somewhere that it is done to avoid version mismatch issues but if its working by installing it globally and simply 'require'ing it in many other languages like Python(uses virtualenv to tackle version issues), Ruby etc., why can't it be the same for node.js? </p>
  
  <p>Whatever happened to DRY?</p>