An illustration of module export behavior in Node

a.js

module.exports = Math.random();

b.js

module.exports = function() {
  return Math.random();
}

main.js

// If you require a module multiple times, you'll always get the same result
console.log(require('./a'));
console.log(require('./a'));
console.log(require('./a'));
console.log(require('./a'));
console.log(require('./a'));
console.log(require('./a'));

// If you want distinct instances, the module can return a factory/constructor
var rand = require('./b');
console.log(rand());
console.log(rand());
console.log(rand());
console.log(rand());
console.log(rand());
console.log(rand());