为node.js回调实现超时

我不熟悉执行此 *** 作的任何库，但连接起来并不难。

// Setup the timeout handlervar timeoutProtect = setTimeout(function() {  // Clear the local timer variable, indicating the timeout has been triggered.  timeoutProtect = null;  // Execute the callback with an error argument.  callback({error:'async timed out'});}, 5000);// Call the async functionasyncFunction(arguments, function() {  // Proceed only if the timeout handler has not yet fired.  if (timeoutProtect) {    // Clear the scheduled timeout handler    clearTimeout(timeoutProtect);    // Run the real callback.    callback();  }});