FooService.js

//1st way

module.exports.foo = function(){
  console.log('foo!')
  }
  
module.exports.bar = function(){
  console.log('bar!')
}



//2nd way

module.exports = {
  foo : function(){
    console.log('foo!')
  },
  bar = function(){
    console.log('bar!')
  }
  
  
}

//in controller

FooService.foo()
FooService.bar()