CoffeeScript always returns in anonymous function

Question

I\'m trying to write some CoffeScript function which checks all checkboxes in a table upon checking the checkbox in the th.

My function in CoffeeScript looks like th

Answer 1

If you just use return (or, equivalently, undefined) as the last line of a function, the CoffeeScript compiler will give you JS with no return at all. So the most efficient way of writing your code would be

$("table.tableview th input:checkbox").live 'click', -> 
  checkedStatus = this.checked
  $("table.tableview tbody tr td:first-child input:checkbox").each ->
    this.checked = checkedStatus
    return
  return

(You can safely do without the second return, of course. Only a return value of false has an effect in jQuery.)

There was also a proposed syntax (-/>) for defining a function with no return value; see issue 899.

Answer 2

Just add a true as the last line of your function, and coffeescript will compile the JS to return that instead:

$("table.tableview th input:checkbox").live 'click', -> 
    checkedStatus = this.checked
    $("table.tableview tbody tr td:first-child input:checkbox").each ->
        this.checked = checkedStatus
    true

In other words, CoffeeScript always returns the result of the last line (like Ruby does)

---

Edit (after the question was updated):

Again, you can't keep CoffeeScript from returning the value of the last line in a function - part of the point of CoffeeScript is that it does exactly that.

CoffeeScript has significant whitespace, so indentation is what says what belongs together - your example is is actually correct:

$("table.tableview th input:checkbox").live 'click', -> 
    checkedStatus = this.checked
    $("table.tableview tbody tr td:first-child input:checkbox").each ->
        this.checked = checkedStatus
        true // cause this function (the each-iterator) to return true
    true // causes the click handler function to return true

There's no difference between this and just writing return true in a function like you would in javascript. You just use whitespace instead of {} to make code blocks.