Using prototypes in other files using node.js

Question

I'm currently learning how to use node.js (And OOP javascript with prototypes) but I've a little problem. I'll give you the code:

foo.js:

var foo = function(){};
foo.prototype.a = function(){
    return 'foo';
};

bar.js:

var bar = new Foo();
console.log(bar.a);

app.js

require('./foo.js');
require('./bar.js');

Instead of working I get a ReferenceError telling me that foo is not defined. Can somebody tell me how I should do this?

You need to understand how Node modules work. In particular, globals aren't really global. nodejs.org/api/modules.html — SLaks
– SLaks, Commented Dec 25, 2013 at 0:12

freakish · Accepted Answer · 2013-12-25 00:14:55Z

2

First, proper export:

foo.js

var foo = function(){};
foo.prototype.a = function(){
    return 'foo';
};

exports.ref_to_foo = foo;

and then proper import:

bar.js

var foo_module = require('./foo.js');
var Foo = foo_module.ref_to_foo;

var bar = new Foo();
console.log(bar.a);

answered Dec 25, 2013 at 0:14

freakish

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2 Comments

Is export a module or is it default in node.js?

@RobinVandenBroeck exports is a special object in each module which is visible outside of the module (and no other object is visible outside).