Assigning to undeclared variable

Question

Please, consider the following code. If I declare the exports field as follows:

exports = 
  someFunc : -> # blablabla
  someOtherFunc : ->

It gets compiled into:

var exports;

exports = {
  someFunc: function() {},
  someOtherFunc: function() {}
};

But as you probably already know I need the exports field to remain undeclared. In other words I need to somehow inform the compiler not to produce the var exports; statement. I know that I can hack around this like that:

exports.someFunc = ->
exports.someOtherFunc = ->

but that's just messy and very much seems like a defect, since the essence of CoffeeScript is to reduce the code noise.

Is there a way or a better hack around this?

score 2 · Answer 1 · answered Feb 15 '12 at 22:00

2

I don't think you can assign directly to exports (in nodejs). I think your code should be

module.exports = 
  someFunc : -> # blablabla
  someOtherFunc : ->

in which case CS will assume module is already defined and will simply output

module.exports = {
  someFunc: function() {},
  someOtherFunc: function() {}
};

answered Feb 15 '12 at 22:00

benekastah

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This is correct. `exports` is a variable with module-wide scope that acts as a reference to `module.exports`. Writing `exports = ...` won't affect `module.exports`. It's an easy mistake to make. – Trevor Burnham Feb 17 '12 at 21:54

score 0 · Accepted Answer · answered Feb 15 '12 at 22:02

I thought of one a bit more clever hack around this, which by accident suits the export needs much better, since it doesn't erase the previously assigned export fields:

exports[k] = v for k, v of {
  someFunc : ->
  someOtherFunc : ->
}

But still it's a hack and it only works for assigning the fields of undeclared objects. How to assign the undeclared variable remains a question.

score -1 · Answer 3 · edited May 23 '17 at 12:27

-1

I'm assuming you "need the exports field to remain undeclared" because you're writing a Node.js module exports is already declared, yes? In that case this question and its top answer ought to go a long way toward helping you: How do I define global variables in CoffeeScript?

In short you'll do something like this:

root = exports ? this

root = 
  someFunc      : -> # blablabla
  someOtherFunc : ->

Hope that helps!

edited May 23 '17 at 12:27

Community

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answered Feb 15 '12 at 21:55

Jordan Running

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Thanks for the link, but your suggestion is wrong since you simply reassign the `root` value in the second statement. I.e., first you assign `root` to `exports ? this`, then you reassign it to the object with the functions. – Nikita Volkov Feb 15 '12 at 22:12

Assigning to undeclared variable

3 Answers3