从Javascript到Coffeescript

Question

So I have this javascript That works by itself

function update_checkboxes()
      {
        var part_array = [];
        $("input#edit:checked").parents('td').next().each(function(){
          part_id = $(this).text();
          part_array.push(part_id);
        });
        $("input#participant_ids").val(JSON.stringify(part_array));
      }

That I converted to coffeescript

update_checkboxes = ->
    part_array = []
    $("input#edit:checked").parents("td").next().each ->
      part_id = $(this).text()
      part_array.push part_id

    $("input#participant_ids").val JSON.stringify(part_array)

The problem is when I do rails rake assets:precompile , it compile fine but in Firebug I gives error

ReferenceError: part_array is not defined

$("input#participant_ids").val(JSON.stringify(part_array));

due that the part_array gets defined in a different block.

update_checkboxes = function() {
    var part_array;
    return part_array = [];
  };

  $("input#edit:checked").parents("td").next().each(function() {
    var part_id;
    part_id = $(this).text();
    return part_array.push(part_id);
  });

  $("input#participant_ids").val(JSON.stringify(part_array));

}).call(this); 

What I'm doing wrong here?

Answer 1

Remember that in CoffeeScript, indentation matters , and you can't mix spaces and tabs reliably.

This CoffeeScript, in which indentation has been standardized to two spaces:

update_checkboxes = ->
  part_array = []
  $("input#edit:checked").parents("td").next().each ->
    part_id = $(this).text()
    part_array.push part_id

  $("input#participant_ids").val JSON.stringify(part_array)

Results in this JavaScript:

var update_checkboxes;
update_checkboxes = function() {
  var part_array;
  part_array = [];
  $("input#edit:checked").parents("td").next().each(function() {
    var part_id;
    part_id = $(this).text();
    return part_array.push(part_id);
  });
  return $("input#participant_ids").val(JSON.stringify(part_array));
};

...which doesn't end up with part_array defined in a separate block.

Answer 2

Your indentation must be off. I pasted your exact coffeescript from the question into js2coffee

update_checkboxes = ->
    part_array = []
    $("input#edit:checked").parents("td").next().each ->
      part_id = $(this).text()
      part_array.push part_id

    $("input#participant_ids").val JSON.stringify(part_array)

and received...

var update_checkboxes;

update_checkboxes = function() {
  var part_array;
  part_array = [];
  $("input#edit:checked").parents("td").next().each(function() {
    var part_id;
    part_id = $(this).text();
    return part_array.push(part_id);
  });
  return $("input#participant_ids").val(JSON.stringify(part_array));
};

Which is correct. StackOverflow must have normalized your indentation when you pasted it. Take a look at the original and fix the mismatched indentation.