javascript - Backbone.js setTimeout() loop in CoffeeScript - Stack Overflow

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Seems like every way I try this, it throws some sort of error. Here's what my code looks like now:

runShow: ->
  moments = @model.get('moment_stack_items')
  if inc == moments.length
    inc = 1
    pre = 0
  $("#" + moments[pre].uid).hide("slide", { direction: "left" }, 1000)
  $("#" + moments[inc].uid).show("slide", { direction: "right" }, 1000)

  inc += 1
  pre += 1

  console.log "looping" + inc
  t = setTimeout(this.runShow(),2000);

I call the function in my events. I have inc = 1 and pre = 0 defined outside the Backbone.View.. My current error is "Uncaught TypeError: Object [object DOMWindow] has no method 'runShow'"
BONUS POINTS: how can I reference t from another function (to run my clearTimeout(t))?

Seems like every way I try this, it throws some sort of error. Here's what my code looks like now:

runShow: ->
  moments = @model.get('moment_stack_items')
  if inc == moments.length
    inc = 1
    pre = 0
  $("#" + moments[pre].uid).hide("slide", { direction: "left" }, 1000)
  $("#" + moments[inc].uid).show("slide", { direction: "right" }, 1000)

  inc += 1
  pre += 1

  console.log "looping" + inc
  t = setTimeout(this.runShow(),2000);

I call the function in my events. I have inc = 1 and pre = 0 defined outside the Backbone.View.. My current error is "Uncaught TypeError: Object [object DOMWindow] has no method 'runShow'"
BONUS POINTS: how can I reference t from another function (to run my clearTimeout(t))?

• javascript
• jquery
• backbone.js
• coffeescript

Share Improve this question Follow edited Aug 18, 2011 at 16:57 pizza247 asked Aug 18, 2011 at 16:17 pizza247pizza247 3,89777 gold badges3535 silver badges4747 bronze badges 2

• Using strings in your setTimeout is calling eval behind the scenes. I would strongly consider changing this to a reference of the function. e.g. t = setTimeout(this.runShow ,2000); stackoverflow./questions/86513/… – Gazler Commented Aug 18, 2011 at 16:43
• fair enough @Gazler, I've removed it from the code. The solution by user576875 also has it removed. – pizza247 Commented Aug 18, 2011 at 16:59

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1 Answer 1

Sorted by: Reset to default 8

You ask the setTimeout function to evaluate "this.runShow()", and setTimeout will do that in the context of window. This means that this is the window object when this code is evaluated.

To avoid this you can create a function and bind it to a the current context, so that everytime the function is called, this is the same as when the function has been created.

In coffee script you can do this with the =>:

func = =>
    this.runShow()

setTimeout(func, 2000)

Or on a single line:

setTimeout((=> this.runShow()), 2000)

how can I reference t from another function?

Make t a property of your object:

class Something
    t: null
    runShow: ->
       ...
       this.t = ...
    otherFunction: ->
       t = this.t

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