rototype.findKey" title="Map.prototype.findKey( callbackfn [ , thisArg ] )"><span class="secnum">3.5</span> Map.prototype.findKey( <var>callbackfn</var> [ , <var>thisArg</var> ] )</a></li><li><span class="item-toggle-none"></span><a href="#Map.prototype.keyOf" title="Map.prototype.keyOf( searchElement )"><span class="secnum">3.6</span> Map.prototype.keyOf( <var>searchElement</var> )</a></li><li><span class="item-toggle-none"></span><a href="#Map.prototype.some" title="Map.prototype.some( callbackfn [ , this