Node.js module.exports in CoffeeScript

Question

Node.js module.exports in CoffeeScript

I'm working on a simple example; I can get it to work with Javascript, but there is something wrong with my CoffeeScript version.

Here is person.coffee:

module.exports = Person

class Person 
    constructor: (@name) ->

    talk: ->
        console.log "My name is #{@name}"

And here is index.coffee:

Person = require "./person"
emma = new Person "Emma"
emma.talk()

I am expecting to run index.coffee and see the console output "My name is Emma". Instead, I am getting an error saying TypeError: undefined in not a function.

node.js
coffeescript

Answer 1

Put the module.exports line at the bottom.

----person.coffee----

class Person 
      constructor: (@name) ->

            talk: ->
                      console.log "My name is #{@name}"

module.exports = Person

coffee> Person = require "./person"
Person = require "./person"
[Function: Person]
coffee> p = new Person "Emma"
p = new Person "Emma"
{ name: 'Emma' }
coffee>

When you assign to module.exports at the top, the Person variable is still undefined.

Answer 2

You could also write in person.coffee:

class @Person

Then use the following in index.coffee:

{Person} = require './person'

Answer 3

You could also write

module.exports = class Person
  constructor: (@name) ->
    console.log "#{@name} is a person"

then in index.coffee either

bob = new require './person' 'Bob'

or you could do it this way

Person = require './person'
bob = new Person 'bob'

Answer 4

The various answers here seems to take for granted that the only one object exported by the module is the class (kind of "Java way of thinking")

If you need to export several objects (classes, functions, etc), it should probably be best to write:

exports.Person = class Person
    [...]

coffee> { Person } = require "./person"
coffee> p = new Person "Emma"