jQuery pipe in CoffeeScript

gistfile1.coffee

each = (list) ->

    return $.Deferred().resolve 'done' if not list?.length

    t = new Date

    $.post('/echo/json/', json: list.shift()).pipe (n) ->
        console.log "round (#{n}) in #{ new Date - t }ms"
        each list


each([0..3]).done (res) ->
    console.log "I've #{res}."


# output below:
###
round (0) in 254ms
round (1) in 263ms
round (2) in 252ms
round (3) in 245ms
I've done.
###


# compiled JavaScript below:
->
    `
    var each;

    each = function(list) {
      var t;
      if (!(list != null ? list.length : void 0)) {
        return $.Deferred().resolve('done');
      }
      t = new Date;
      return $.post('/echo/json/', {
        json: list.shift()
      }).pipe(function(n) {
        console.log("round (" + n + ") in " + (new Date - t) + "ms");
        return each(list);
      });
    };

    each([0, 1, 2, 3]).done(function(res) {
      return console.log("I've " + res + ".");
    });
    `