index.js

"use strict"

if (typeof setImmediate == 'function') {
  module.exports = function(f){ setImmediate(f) }
}
// legacy node.js
else if (typeof process != 'undefined' && typeof process.nextTick == 'function') {
  module.exports = process.nextTick
}
// fallback for other environments / postMessage behaves badly on IE8
else if (typeof window == 'undefined' || window.ActiveXObject || !window.postMessage) {
  module.exports = function(f){ setTimeout(f) };
} else {
  var q = [];

  window.addEventListener('message', function(){
    var i = 0;
    while (i < q.length) {
      try { q[i++](); }
      catch (e) {
        q = q.slice(i);
        window.postMessage('tic!', '*');
        throw e;
      }
    }
    q.length = 0;
  }, true);

  module.exports = function(fn){
    if (!q.length) window.postMessage('tic!', '*');
    q.push(fn);
  }
}