Question

I’m translating a piece of code from javascript to coffeescript.

  for (var i = 0, len = keys.length; i < len; i++) {
    k = keys[i];
    if (!mailOptions.hasOwnProperty(k))
      mailOptions[k] = app.set('mailOptions')[k]
  }

I have no idea how to approach to it and on the doc website is not clear, can someone give me a clear explanation? thank you very much!

Answer 1

for key in keys
  if not mailOptions.hasOwnProperty key
    mailOptions[key] = (app.set 'mailOptions')[key]

Or guard-style:

for key in keys when not mailOptions.hasOwnProperty key
  mailOptions[key] = (app.set 'mailOptions')[key]

Compiles to:

var key, _i, _len;

for (_i = 0, _len = keys.length; _i < _len; _i++) {
  key = keys[_i];
  if (!mailOptions.hasOwnProperty(key)) {
    mailOptions[key] = (app.set('mailOptions'))[key];
  }
}