Express Routing (GET, POST, PUT, DELETE)

Defining HTTP Route Handlers

Routing determines how an application responds to a client request to a particular endpoint, which is a URI (or path) and a specific HTTP request method.

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

app.use(express.json()); // Middleware to parse incoming JSON bodies

// GET: Retrieve resource list
app.get("/api/products", (req, res) => {
  res.json([{ id: 1, name: "Laptop", price: 999 }]);
});

// POST: Create a new resource
app.post("/api/products", (req, res) => {
  const newProduct = req.body;
  res.status(201).json({ message: "Product created", product: newProduct });
});

// PUT: Update resource completely
app.put("/api/products/:id", (req, res) => {
  const { id } = req.params;
  res.json({ message: `Product ${id} updated`, data: req.body });
});

// DELETE: Remove resource
app.delete("/api/products/:id", (req, res) => {
  const { id } = req.params;
  res.status(200).json({ message: `Product ${id} deleted` });
});

Route Matching Rules

• Paths match string literals ('/api/users').
• Paths match string patterns ('/ab?cd', '/users/:id').
• Methods match specific HTTP verbs (app.get, app.post, app.put, app.delete, app.patch, app.all).

TL;DR

• Map HTTP CRUD verbs to Express routing methods: GET (Read), POST (Create), PUT/PATCH (Update), DELETE (Delete).