Calling functions defined with coffee script?

Question

I have the following coffeescript code to generate and alert box:

show_alert = () ->
  alert("Hello! I am an alert box!")

which compiles to:

(function() {
  var show_alert;

  show_alert = function() {
    return alert("Hello! I am an alert box!");
  };

}).call(this);

in my html I have the following

<input onclick='show_alert()' type='button' value='Show alert box' />

However, no alert box shows? The following is the html copied from the browser:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
  <head>
    <title>Test Rails Application</title>
    <style type='text/css'>.application h1 {
  color: lime; }
</style>
    <script type='text/javascript'>(function() {
  var show_alert;

  show_alert = function() {
    return alert("Hello! I am an alert box!");
  };

}).call(this);
</script>
  </head>
  <body>
    <h1>Hello from applicaiton.html.haml</h1>
    <div class='application'><h1>Hello World</h1>
<input onclick='show_alert()' type='button' value='Show alert box' />
</div>
  </body>
</html>

Why am I not able to get an alert box to show up?

score 23 · Accepted Answer · edited May 23 '17 at 11:58

Your problem is that the generated javascript code is in another scope. You have to solve this by either adding the -b parameter to the coffeescript compiler or export your function explicitly via

root = exports ? this
root.show_alert = () -> alert("Hello! I am an alert box!")

For more information about the exporting and scope issue have a look at https://stackoverflow.com/a/4215132/832273

I created a working jsfiddle with the above coffeescript code

score 11 · Answer 2 · answered Jun 09 '14 at 11:31

11

I found two ways to solve this issue FIRST add @ before function name

@say_hi = () ->
  $(alert('Hello!!!'))

SECOND at the end of coffee file add

window["say_hi"] = say_hi

answered Jun 09 '14 at 11:31

kapellan

301
4
6

score 4 · Answer 3 · answered May 05 '12 at 04:42

4

in your coffeescrpt code, try to save the function to window: window["show_alert"] = show_alert

answered May 05 '12 at 04:42

akonsu

28,824
33
119
194

1

jftr i think `root = exports ? this; root.show_alert = show_alert` is better instead of directly accessing window. See http://stackoverflow.com/a/4215132/832273 for details – Ulrich Dangel May 05 '12 at 04:45
@mru javascript is always extremely confusing to me. Is there a specific reference site or text either of you would recommend? – rudolph9 May 05 '12 at 05:01
1

@KurtRudolph depends on what you are looking for but have a look at https://developer.mozilla.org/en/JavaScript – Ulrich Dangel May 05 '12 at 05:05

Calling functions defined with coffee script?

3 Answers3