Timestamp Microservice

I recently started working on the back-end certification for FreeCodeCamp and the first challenge is to build a simple application using Node.js and Express. The app is a simple server and router which takes a URL string as a parameter and returns both a Unix timestamp and a natural-language date (e.g. Jan 1, 2017).

I’ve used Node before, but this was my first time trying out Express, which is a web application framework for Node. So, to get started, we just require(...) it like any other package in Node:

const express = require('express');
const app = express();
const port = process.env.PORT; // <- this is the port that Express will listen to

Next, we want to route a GET request, which Express can do with app.get('URL', function(request, response){...}). The first argument here is the URL string that the user enters into the navigation bar. According to the Express documentation, we can use the pattern /:var to store the string as a variable in request.params.var. The request and response arguments in the callback function are useful for receiving a query and sending back a response to the client. Once we analyze the GET request, we can send back data with response.send(someObj).

In the code below, we get the time string parameter out of the request.params object. If it is a number, we set the date variable with it using the Date() constructor; or, if the URL string is already natural-language, we let that be the date variable and use the Date() constructor and the .valueOf() method to get its Unix time.

app.get('/:foo', function (req, res) {
  var time = req.params.foo;
  if (!isNaN(time)) {
    var date = new Date(Number(time)).toDateString();
  }
  else {
    var date = time;
    var time = new Date(date).valueOf().toString();
  }
  res.send({
    unix: time,
    natural: date
  });
})

Finally, we send an object in the response with the variables that we calculated previously. Now we just need a way for the app to listen on a port, which we can do simply with app.listen() and using the constant port we defined earlier:

app.listen(port, function () {
  console.log('Listening on port '+ port +'!')
})

Now, we can go to the specified port (on my console it is 8080) and see that the app is running. If we go to the address bar, we can pass in any number (Unix time) and see the JSON response reporting the Unix timestamp and the natural-language equivalent. If we pass in a natural date (like /January 1, 2017), we see that the response again reports both. We don’t even need to encode our URL string when we type it in!

Wanna try it out?