Inject environment variables when returning the index file

app.js

var environment = {
  env: process.env.NODE_ENV || 'local'
};

var envRegex = /\/\/node::environment\s/;
var envString = 'environment = ' + JSON.stringify(environment) + '; //';

var injectEnvironment = function injectEnvironment(req, res) {
  fs.readFile(path.join(__dirname, '/app/index.html'), function(err, file) {
    res.send(file.toString().replace(envRegex, envString));
  });
};

app.get('/index.html', injectEnvironment);

// Use the following in your index.html (inside <script> tags) file to inject:
// node::environment 
// it will place the environment object there, obviously you would want to Angular-ize it instead of being a global variable.