CODEWITHSUNDEEP
coffeescript
captncraig
captncraig

Reputation: 23108

Public class members in coffeescript

I am very new to coffeescript, and I have been trying to find a way to make publicly accessible class members. If I run the following code:

class cow
  n = 7
  moo: -> 
    alert("moo")

bessie = new cow
alert(bessie.n);

It will show that bessie.n is undefined. The only solution I can find is to make getters and setters like n: -> n and setN: (value) -> n = value. I then must use function calls instead of simple property accesses. This feels cumbersome for a language which sells itself based on syntactic sugar.

Is there something I missed in the documentation that makes it easier to make classes with simple public members? What is the best practice for this?

Upvotes: 3

Views: 3182

Answers (2)

user1040252
user1040252

Reputation: 21

when you need a private member, you typically can't use a private static member in its place.

The concept of private variables is easily implemented via Crockfords suggestions, but this isn't a proper CoffeeScript class and as such you can't extend it. The winner is that you get an object with methods where no one else can read/write your variable making it a little more foolproof. Note you don't use the 'new' keyword (which Crockford considers a bad practice anyway)

Counter = (count, name) ->
    count += 1
    return {
        incr : ->
            count = count + 1
        getCount : ->
            count
    }

c1 = Counter 0, "foo"
c2 = Counter 0, "bar"
c3 = Counter 0, "baz"

console.log c1.getCount() # return 1 regardless of instantiation number
console.log c1.count # will return undefined

Upvotes: 0

esamatti
esamatti

Reputation: 18953

It's no different from setting methods.

Just try this

class cow
  n: 7

Doing only

class cow
  n = 7

Will just set private variable inside the class closure.

Use try coffeescript link on http://coffeescript.org/ to see what it compiles to.

Upvotes: 10

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