ExpressJS cheatsheet

Syntax snippets and quick notes for revision.

Express Introduction

import express from "express";
const app = express();
app.use(express.json());
app.post("/api/express-introduction", (req, res) => res.json({ success: true, processed: req.body }));

Use this express introduction pattern when a ExpressJS task needs a small, readable starting point.

Express Setup

import express from "express";
const app = express();
app.use(express.json());
app.post("/api/express-setup", (req, res) => res.json({ success: true, processed: req.body }));

Use this express setup pattern when a ExpressJS task needs a small, readable starting point.

Basic Routing

import express from "express";
const app = express();
app.use(express.json());
app.post("/api/basic-routing", (req, res) => res.json({ success: true, processed: req.body }));

Use this basic routing pattern when a ExpressJS task needs a small, readable starting point.

Request and Response

import express from "express";
const app = express();
app.use(express.json());
app.post("/api/request-and-response", (req, res) => res.json({ success: true, processed: req.body }));

Use this request and response pattern when a ExpressJS task needs a small, readable starting point.

Express Middleware

app.use((req, res, next) => {
  console.log(`[${new Date().toISOString()}] ${req.method} ${req.url}`);
  next();
});

Use this express middleware pattern when a ExpressJS task needs a small, readable starting point.

Serving Static Files

import express from "express";
const app = express();
app.use(express.json());
app.post("/api/serving-static-files", (req, res) => res.json({ success: true, processed: req.body }));

Use this serving static files pattern when a ExpressJS task needs a small, readable starting point.

JSON Parsing

import express from "express";
const app = express();
app.use(express.json());
app.post("/api/json-parsing", (req, res) => res.json({ success: true, processed: req.body }));

Use this json parsing pattern when a ExpressJS task needs a small, readable starting point.

URL Parameters

import express from "express";
const app = express();
app.use(express.json());
app.post("/api/url-parameters", (req, res) => res.json({ success: true, processed: req.body }));

Use this url parameters pattern when a ExpressJS task needs a small, readable starting point.

Query Strings

import express from "express";
const app = express();
app.use(express.json());
app.post("/api/query-strings", (req, res) => res.json({ success: true, processed: req.body }));

Use this query strings pattern when a ExpressJS task needs a small, readable starting point.

Router Module

import express from "express";
const app = express();
app.get("/api/orders", (req, res) => {
  res.json({ id: 42, total: 59, status: "paid" });
});

Use this router module pattern when a ExpressJS task needs a small, readable starting point.

Error Handling Middleware

app.use((req, res, next) => {
  console.log(`[${new Date().toISOString()}] ${req.method} ${req.url}`);
  next();
});

Use this error handling middleware pattern when a ExpressJS task needs a small, readable starting point.

CORS Configuration

import express from "express";
const app = express();
app.use(express.json());
app.post("/api/cors-configuration", (req, res) => res.json({ success: true, processed: req.body }));

Use this cors configuration pattern when a ExpressJS task needs a small, readable starting point.