What means this part of JavaScript code : <p>please i need to know what means this part of code, i couldn't especially  understand the condition</p>

<pre><code>var classie = {
  // full names
  hasClass: hasClass,
  addClass: addClass,
  removeClass: removeClass,
  toggleClass: toggleClass,
  // short names
  has: hasClass,
  add: addClass,
  remove: removeClass,
  toggle: toggleClass
};

// transport
if ( typeof define === 'function' &amp;&amp; define.amd ) {
  // AMD
  define( classie );
} else {
  // browser global
  window.classie = classie;
}
</code></pre>
