Coffeescript #troll

gistfile1.coffee

raf = 'RequestAnimationFrame'
window['r' + raf[1..]] ?= do ->
    return R for pre in ['webkit', 'moz', 'ms', 'o'] when R = window[pre + raf]

# =.=.=.=.=.=.=.=.=.=.=.=.=.=

raf = 'RequestAnimationFrame';

if (window[_name = 'r' + raf.slice(1)] == null) {
  window[_name] = (function() {
    var R, pre, _i, _len, _ref;
    _ref = ['webkit', 'moz', 'ms', 'o'];
    for (_i = 0, _len = _ref.length; _i < _len; _i++) {
      pre = _ref[_i];
      if (R = window[pre + raf]) return R;
    }
  })();
}





do ->
    raf = 'RequestAnimationFrame'
    window['r' + raf[1..]] ?= do ->
        return R for pre in ['webkit', 'moz', 'ms', 'o'] when R = window[pre + raf]

# =.=.=.=.=.=.=.=.=.=.=.=.=.=

(function() {
  var raf, _name, _ref;
  raf = 'RequestAnimationFrame';
  return (_ref = window[_name = 'r' + raf.slice(1)]) != null ? _ref : window[_name] = (function() {
    var R, pre, _i, _len, _ref2;
    _ref2 = ['webkit', 'moz', 'ms', 'o'];
    for (_i = 0, _len = _ref2.length; _i < _len; _i++) {
      pre = _ref2[_i];
      if (!(R = window[pre + raf])) {}
    }
  })();
})();

O que eu acabei usando:

window.requestAnimationFrame ?= 
    window.webkitRequestAnimationFrame or
    window.mozRequestAnimationFrame or
    window.msRequestAnimationFrame or
    window.oRequestAnimationFrame or
    (fn, el) -> setTimeout fn, 1000/60

Resultado:

if (window.requestAnimationFrame == null) {
  window.requestAnimationFrame = window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.msRequestAnimationFrame || window.oRequestAnimationFrame || function(fn, el) {
    return setTimeout(fn, 1000 / 60);
  };
}

O negócio é evitar for pra ter código mais limpo:

vendors = ['webkit', 'moz', 'ms', 'o']
i = 0
while !window.requestAnimationFrame && i < vendors.length
    window.requestAnimationFrame = window[vendors[i++]+'RequestAnimationFrame']

window.requestAnimationFrame or= (cb) -> setTimeout cb, 1000/60

Compila lindamente:

var i, vendors;
vendors = ['webkit', 'moz', 'ms', 'o'];
i = 0;
while (!window.requestAnimationFrame && i++ < vendors.length) {
  window.requestAnimationFrame = window[vendors[i] + 'RequestAnimationFrame'];
}

window.requestAnimationFrame || (window.requestAnimationFrame = function(cb) {
  return setTimeout(cb, 1000 / 60);
});

Neste teu exemplo o i precisa começar de -1

Ooops. Já ta na grifo a essa hora?