Express API
- Node.js course
- Intermediate
- Lesson 113/116
- 6 min
Set up the REST API skeleton with Express.
User routes
In this lesson we add two routes for the /users resource: GET /users returns the user list, POST /users creates a new user. In Express app.get and app.post are separate methods; they register different handlers for the same path.
In handlers res.json(data) sends the response as JSON. GET /users can return an empty array []; POST /users can return {created: true}. You also add each route to the array with routes.push(...). Then routes.map(r => r.method + ' ' + r.path).join(', ') prints the routes as one string. This is a clean way to summarize the API surface.
Printing the routes
To print all routes as one string you use routes.map(...).join(', '). map turns each route into a string; join combines them with a comma. This summarizes the API surface.
Example: routes.map(r => r.method + ' ' + r.path).join(', '). With three routes the output is GET /health, GET /users, POST /users. join(', ') places a comma and space between items. This is a practical way to inspect routes within the program. console.log('Routes: ' + ...) adds a label prefix.
Practice Add the user routes
Add app.get('/users', (req, res) => res.json([])). Record it with routes.push({method: 'GET', path: '/users'}). Add app.post('/users', (req, res) => res.json({created: true})). Record with routes.push({method: 'POST', path: '/users'}). Print console.log('Routes: ' + routes.map(r => r.method + ' ' + r.path).join(', ')).
Starter code
const express = require('express');
const app = express();
const routes = [];
app.get('/health', (req, res) => res.json({ok: true}));
routes.push({method: 'GET', path: '/health'});
console.log('Server ready');
// Add the GET /users and POST /users routes
// Print the routes
// write hereSample solution
const express = require('express');
const app = express();
const routes = [];
app.get('/health', (req, res) => res.json({ok: true}));
routes.push({method: 'GET', path: '/health'});
console.log('Server ready');
app.get('/users', (req, res) => res.json([]));
routes.push({method: 'GET', path: '/users'});
app.post('/users', (req, res) => res.json({created: true}));
routes.push({method: 'POST', path: '/users'});
console.log('Routes: ' + routes.map(r => r.method + ' ' + r.path).join(', '));Expected output
Sunucu hazır Rotalar: GET /health, GET /users, POST /users
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Define the GET route
app.____('/users', (req, res) => res.json([]));app.get('/users', (req, res) => res.json([]));Explanation: app.get registers a GET route.
2 Match each piece to its role
| Term | Meaning |
|---|---|
app.get |
Registers a GET route |
app.post |
Registers a POST route |
res.json |
Sends a JSON response |
.map |
Transforms each item |
3 What does routes.map(r => r.method + ' ' + r.path) produce?
routes.map(r => r.method + ' ' + r.path)- Yol dizesi dizisi Correct answer
- An array of numbers
- Boole dizisi
- Bir promise
Explanation: map turns each route into a 'METHOD path' string.