Requires in js

a.js

// a.js
var add = function(a, b) {
  return a + b;
};

module.exports = add;

app.js

require('./a');
require('./b');

// Want it to generate something like this:

"use strict";
// b.js
// a.js
var add = function(a, b) {
  return a + b;
};
console.log(add(2, 3));

// But it generates:

"use strict";

// b.js
require("./foo");                                                                                                                              
console.log(add(2, 3));

// a.js
var add = function (a, b) {
  return a + b;
};

module.exports = add;

b.js

// b.js
require('./a');
console.log(add(2, 3));

In b.js:

var add = require('./a');
console.log(add(2, 3));

And a note about app.js- each module is only loaded a single time, at which point its export is cached in memory. So if you want to reuse b, you will want to export a function or an object.

b:

var add = require('./a');
module.exports = function () { console.log(add(1,2)); };

app:

var b = require('./b');
b();
b();

I was wanting to do this for front-end only, via gulp, and happened upon https://www.npmjs.com/package/gulp-resolve-dependencies