How to define routes on the app directly — Basic
Attach handlers with app.get/post before splitting logic into router modules.
Learn: Defining routes directly on `app` is fine for tiny projects or quick experiments. As endpoints multiply, inline handlers become hard to test and navigate—splitting into router modules keeps each file responsible for one resource area.
Supplementary examples
GET and POST on the app
app.get("/pastes", (req, res, next) => list(req, res, next));
app.post("/pastes", (req, res, next) => create(req, res, next));Route parameters on the app
app.get("/users/:userId", (req, res) => {
const { userId } = req.params;
res.json({ userId });
});Course example
// New middleware function to validate the request body
function bodyHasTextProperty(req, res, next) {
const { data: { text } = {} } = req.body;
if (text) {
return next(); // Call `next()` without an error message if the result exists
}
next("A 'text' property is required.");
}
let lastPasteId = pastes.reduce((maxId, paste) => Math.max(maxId, paste.id), 0);
app.post(
"/pastes",
bodyHasTextProperty, // Add validation middleware function
(req, res) => {
// Route handler no longer has validation code.
const { data: { name, syntax, exposure, expiration, text, user_id } = {} } = req.body;
const newPaste = {
id: ++lastPasteId, // Increment last id then assign as the current ID
name,
syntax,
exposure,
expiration,
text,
user_id,
};
pastes.push(newPaste);
res.status(201).json({ data: newPaste });
}
);Additional references & examples
- Express.js guide
Routing, middleware order, and request/response lifecycle.
- RESTful API design (readthedocs)
Resource naming and HTTP verb conventions (cited in course).
- HTTP status codes (MDN)
When to use 200, 201, 204, 400, 404, 500, and related codes.