Question

If I have a code like this:

class SomeClass
  constructor: ->
    @someAttr = false

  someFunction: ->
    process.nextTick ->
      @someAttr = true

obj = new SomeClass
obj.someFunction()
obj.someAttr # Would still be false, because the @ (this) is in the process context

it won’t work, because process.nextTick brings us into a different context, in which @someAttr isn’t defined. How can I work around this (also when I want to call methods of SomeClass)?

Answer 1

The usual way around this is to store a reference to this in a local variable which will be available within the anonymous function. In JavaScript:

function someFunction() {
  var self = this;
  process.nextTick(function() {
    self.someAttr = true;
  });
}

CoffeeScript has a special syntax to help with this; the “fat arrow“:

class SomeClass:
  someFunction: ->
    process.nextTick =>
      @someAttr = true