Question

I have the following For Of loop in CoffeeScript that loops through the properties of an object:

for buildingFrame of buildingNames
  $("#bt-#{buildingFrame}").click () => @displayProperties(buildingFrame)

It appears that only the last value of buildingFrame is passed to every call to @displayProperties. Searching the site I found what I think is the reason here: Possible Answer

The reason why only the last value in the loop is used is because JavaScript is a late-binding language and loops do not introduce a new scope. The solution to fix this is given in that answer in JavaScript like so:

for(var i=0; i<barValues.length; i++) function(i){
  ...
}(i);

I have tried using this solution to my coffeScript above to try and solve the problem like so:

for buildingFrame of buildingNames => (buildingFrame)
  $("#bt-#{buildingFrame}").click () => @displayProperties(buildingFrame)
(buildingFrame)

But this just gives my complier errors. Coud someone please advise me how I can tackle this problem in CS. Thanks everyone!

Answer 1

How about something like this?

for buildingFrame of buildingNames
  do (buildingFrame) =>
    $("#bt-#{buildingFrame}").click => @displayProperties(buildingFrame)

This compiles into the following JavaScript:

_fn = function(buildingFrame) {
  return $("#bt-" + buildingFrame).click(function() {
    return _this.displayProperties(buildingFrame);
  });
};

for (buildingFrame in buildingNames) {
  _fn(buildingFrame);
}