Closured constructor locals in CoffeeScript

Question

Sometimes I write my JS classes like this:

mylib.Container = function() {
  var things = [];

  // Returns the index of the image added
  this.addItem = function(item)
  {
    things.push(item)
  }
}
...
var c = new mylib.Container();
c.addItem(whatever);

I use "constructor-scoped" closured variables (like things) to avoid this scoping issues, and I am also using them in tight loops (like the ones used in requestAnimationFrame). These variables never bleed to the outside of the created fubject.

Is there a way to create and use such variables in CoffeeScript? I know that I have the @ivar notation which is shorter than this but something is telling me acessing a closured varmight still be faster...

Also similar to [How to make method private and inherit it in Coffeescript?](http://stackoverflow.com/q/10612293/479863) or at least the answer might be useful. — mu is too short, Mar 26 '13 at 17:12

score 0 · Accepted Answer · answered Mar 26 '13 at 11:14

0

In your code, you're assigning function in the constructor. You can do that in coffee as well

myLib.container = ->
  things = []

  @addItem = (item) -> things.push item

  this

or if you really want to use the class syntax

class myLib.container
  constructor: ->
    things = []
    @addItem = (item) -> things.push item

answered Mar 26 '13 at 11:14

Ven

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If I do this using the class syntax, `things` will not be available outside of the constructor scope. Or is constructor scope the same as the function scope in my example? – Julik Mar 26 '13 at 13:10
That's why I added `@addItem` in the constructor – Ven Mar 26 '13 at 18:20

Closured constructor locals in CoffeeScript

1 Answers1