Why testing APIs matters in Express - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a simple Express server that listens on port 3000.

Express

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen([1], () => {
  console.log('Server running');
});

Drag options to blanks, or click blank then click option'

A5000

B8080

C3000

D80

Attempts:

3 left

💡 Hint

Common Mistakes

Using port 80 without admin rights

Using a string instead of a number

The server listens on port 3000, which is a common default for Express apps.

2fill in blank

medium

Complete the code to add JSON body parsing middleware to the Express app.

Express

const express = require('express');
const app = express();

app.use([1]());

app.post('/data', (req, res) => {
  res.json(req.body);
});

Drag options to blanks, or click blank then click option'

Aexpress.json

BbodyParser.json

CjsonParser

Dexpress.body

Attempts:

3 left

💡 Hint

Common Mistakes

Using deprecated body-parser package

Calling middleware without parentheses

Express has built-in JSON parsing middleware called express.json().

3fill in blank

hard

Fix the error in the route handler to correctly send a JSON response with a message.

Express

app.get('/status', (req, res) => {
  res.[1]({ message: 'API is working' });
});

Drag options to blanks, or click blank then click option'

Ajson

BsendJson

CsendText

DsendMessage

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent methods like sendJson

Using sendText which sends plain text

The res.json() method sends a JSON response.

4fill in blank

hard

Fill both blanks to create a middleware that logs the HTTP method and URL of each request.

Express

app.use((req, res, next) => {
  console.log(req.[1] + ' ' + req.[2]);
  next();
});

Drag options to blanks, or click blank then click option'

Amethod

Burl

Cpath

Dbody

Attempts:

3 left

💡 Hint

Common Mistakes

Using req.path instead of req.url

Logging req.body which is the request data

req.method gives the HTTP method and req.url gives the requested URL.

5fill in blank

hard

Fill all three blanks to create a route that responds with a status code 201 and a JSON message.

Express

app.post('/create', (req, res) => {
  res.status([1]).[2]([3]);
});

Drag options to blanks, or click blank then click option'

A201

Bjson

C{ message: 'Resource created' }

Dsend

Attempts:

3 left

💡 Hint

Common Mistakes

Using status code 200 instead of 201

Using send instead of json for JSON response

The status code 201 means 'Created'. Use res.status(201).json({ message: 'Resource created' }) to send the response.