code: function onFunction(data, op, iterStr, context) {
  	var	iter,
  		data;
  		
  	// Check task
  	if(!op || !data || !iterStr || !context) {
  		throw Error('Worker received invalid task');
  	}
  	
  	// parse the serialized function
  	// eval() may be evil but here we don't have much choice
  	eval('var iter = ' + iterStr);
  
  	switch(op) {
  		case 'map':
  			data = data.map(iter);
  			break;
  		case 'filter': 
  			data = data.filter(iter);
  			break;
  		default:
  			data = null;
  			break;
  	}
  	
  	process.send({
  		result: data,
  		context: context
  	});
  }
docs: Handle functional requests