boilerplate.js

(function(){

    function Klass(id){ this._id = id; }
    Klass.prototype.id = function(){ console.log(this._id); }

    var freeExports = typeof exports == 'object' && exports;
    if (freeExports) {
        for (var prop in Klass) freeExports[prop] = Klass[prop];
    } else if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
        define(function() { return Klass; });
    } else {
        // use square bracket notation so Closure Compiler won't mung `Klass`
        // http://code.google.com/closure/compiler/docs/api-tutorial3.html#export
        window['Klass'] = Klass;
    }
})();

nodejs_require.txt

> var Klass = require('./js/boilerplate.js')
> var foo = new Klass('foo')
TypeError: object is not a function
    at Object.CALL_NON_FUNCTION_AS_CONSTRUCTOR (native)
    at [object Context]:1:11
    at Interface.<anonymous> (repl.js:171:22)
    at Interface.emit (events.js:64:17)
    at Interface._onLine (readline.js:153:10)
    at Interface._line (readline.js:408:8)
    at Interface._ttyWrite (readline.js:585:14)
    at ReadStream.<anonymous> (readline.js:73:12)
    at ReadStream.emit (events.js:81:20)
    at ReadStream._emitKey (tty_posix.js:307:10)
>