In the route app.get('/now', ...) chain a middleware function and the final handler. In the middleware function you should add the current time to the request object in the req.time key. You can use new Date().toString(). In the handler, respond with a JSON object, taking the structure {time: req.time}.

Here is a step-by-step guide on how to chain a middleware function and the final handler in Express.js:

1. First, you need to define your middleware function. This function will add the current time to the request object in the req.time key. Here's how you can do it:

let addTime = (req, res, next) => {
  req.time = new Date().toString();
  next();
};

2. Next, you need to chain this middleware function to your route. You can do this by passing the middleware function as a second argument to the app.get() function, before the final handler function:

app.get('/now', addTime, (req, res) => {
  // final handler code here
});

3. In the final handler, you need to respond with a JSON object that includes the time from the req.time key. You can do this using the res.json() function:

app.get('/now', addTime, (req, res) => {
  res.json({time: req.time});
});

So, the complete code would look like this:

let addTime = (req, res, next) => {
  req.time = new Date().toString();
  next();
};

app.get('/now', addTime, (req, res) => {
  res.json({time: req.time});
});

This code will add the current time to the request object in the middleware function, then respond with a JSON object that includes this time in the final handler.