javascript - CoffeeScript Object Property Pointing to the Same Object -

i have class use 2 separate objects. class has property myvar, object itself. should different each object. however, in instantiated objects myvar properties point same object, see code below. how can have unique/private myvar property each object?

class test   myvar: {}  obj = new test obj2 = new test obj.myvar['key'] = 'value'  console.log obj.myvar # result: { key: 'value' } / correct console.log obj2.myvar # result: { key: 'value' } / incorrect! expected {}! 

compiled javascript:

// generated coffeescript 1.6.3 (function() {   var test, obj, obj2;    test = (function() {     function test() {}      test.prototype.myvar = {};      return test;    })();    obj = new test;    obj2 = new test;    obj.myvar['key'] = 'value';    console.log(obj.myvar);    console.log(obj2.myvar);  }).call(this); 

update. have found possible "solution": put properties objects constructor, see below. there better solution?

class test   constructor: ->     @myvar = {} 

no, there isn't better solution setting instance variables in constructor:

class test   constructor: ->     @myvar = {} 

anything in class definition attached prototype they're shared instances else in prototype. quick @ javascript might helpful:

var test; test = (function() {   function test() {}   test.prototype.myvar = {};   return test; })(); 

you can safely put immutable things (such strings, numbers, , booleans) in class definition not mutable values. example, fine:

class c   s: 'pancakes' 

because way change s replace completely:

c = new c c.s = 'house' 

and shadows prototype value rather modifying it.