CoffeeScript and OOP - prototype methods

Question

Let's say I do the following code:

class Test
  t: ->
    "hell"
  d: ->
    console.log t()
    "no"

It will compile to something like:

(function() {
  this.Test = (function() {
    function Test() {}
    Test.prototype.t = function() {
      return "hell";
    };
    Test.prototype.d = function() {
      console.log(t());
      return "no";
    };
    return Test;
  })();
}).call(this);

Ok, I can't call the method t() inside the d() method.

Why not? How can I fix it?

Thanks in advance.

Alex Wayne · Accepted Answer · 2013-01-15 20:46:07Z

10

class Test
  t: ->
    "hell"
  d: ->
    console.log @t()
    #           ^ Added
    "no"

In CoffeeScript, as in Javascript, methods on the prototype must be accessed as properties of this. CoffeeScript has shorthand for this, the @ character. @t() compiles to this.t(). And this.t() will execute Test.prototype.t() in the context on the instance you called it on.

answered Jan 15, 2013 at 20:46

Alex Wayne

188k52 gold badges328 silver badges363 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

caarlos0 Over a year ago

gotcha. I need to tell to use this instance method, otherwise it will try to use a static method. Am I right? BTW: Thanks

Alex Wayne Over a year ago

@caarlos0 Not quite. @t() will execute an instance method, but t() won't access a static method on the class. t() looks for a local variable function shared in the current closure scope, and tries to execute it. This is neither a instance or static method, it's simply a local variable. And in this code, there is no local variable t anywhere.

Collectives™ on Stack Overflow

CoffeeScript and OOP - prototype methods

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related