example‐1.js

// This does pretty much the thing that Node.js’s `require()` does. In this
// example, ‘exports is undefined’ never gets printed. This is as expected.
var wrapper = eval("var __wrap__ = function (exports) {" + '\n' + 
"(function () {" + '\n' + 
"  if (typeof exports === 'undefined') { alert('exports is undefined' + '\\n') };" + '\n' + 
"  if (typeof exports === 'undefined') { exports = {} };" + '\n' + 
"})()" + '\n' + 
"}; __wrap__;", '');

var exports_obj = new(Object);
wrapper.apply(exports_obj, [exports_obj]);

example‐2.js

// This does pretty much the thing that Node.js’s `require()` does. In this
// example (notice the `var` keyword on line 7), ‘exports is undefined’ gets
// printed. This makes no sense, because it very definitely *is* defined.
var wrapper = eval("var __wrap__ = function (exports) {" + '\n' + 
"(function () {" + '\n' + 
"  if (typeof exports === 'undefined') { alert('exports is undefined' + '\\n') };" + '\n' + 
"  if (typeof exports === 'undefined') { var exports = {} };" + '\n' + 
"})()" + '\n' + 
"}; __wrap__;", '');

var exports_obj = new(Object);
wrapper.apply(exports_obj, [exports_obj]);