Why is coffescript creating this closure

Question

I'm learning CoffeeScript I have this code:

class Person
    constructor: (@firstName, @lastName) ->
    sayHi: () ->
        return "Hi, I'm #{@firstName} #{@lastName}"

And is generating this javascript code:

// Generated by CoffeeScript 1.10.0
(function() {
  var Person;

  Person = (function() {
    function Person(firstName, lastName) {
      this.firstName = firstName;
      this.lastName = lastName;
    }

    Person.prototype.sayHi = function() {
      return "Hi, I'm " + this.firstName + " " + this.lastName;
    };

    return Person;

  })();

}).call(this);

I want to create instances of that class, but since it's inside the closure I can't how should I do that?

I'm not using `node`. Just `npm` for install some packages but it is just front end app for now — Pablo, Jan 21 '16 at 19:19
I want to run jasmine tests over this, but when I `require` the js file, Person is undefined since it is in the closure — Pablo, Jan 21 '16 at 19:21
http://stackoverflow.com/questions/4214731/coffeescript-global-variables — Ruan Mendes, Jan 21 '16 at 19:21

score 1 · Accepted Answer · edited May 23 '17 at 12:33

An option that is slightly less hackish is the @ operator (which is the same as this). In a browser environment, this will point to window, in node.js, it will point to exports.

class @Person
  constructor: (@firstName, @lastName) ->
  sayHi: () ->
    return "Hi, I'm #{@firstName} #{@lastName}"

window.Person only works on the browser, the @ will work for node and the browser. See https://stackoverflow.com/a/24352630/227299

Alternatively, you can run coffescript with the -b (--bare) option and the wrapping function won't be created.

score 0 · Answer 2 · answered Jan 21 '16 at 19:13

0

change a bit declaration of a class

class window.Person
  constructor: (@firstName, @lastName) ->
  sayHi: () ->
    return "Hi, I'm #{@firstName} #{@lastName}"

answered Jan 21 '16 at 19:13

djaszczurowski

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is this the correct way to make it work in `coffee`? – Pablo Jan 21 '16 at 19:16

Why is coffescript creating this closure

2 Answers2