JSON Middleware

Manually parsing the request body with streams is pretty tedious. Luckily, Express has convenient built-in middleware to parse JSON request bodies. All you need is:

import express from "express";

const app = express();

// Built-in JSON body parsing middleware
app.use(express.json());

Express will automatically:

• Check if the Content-Type header is set to application/json
• Parse the request into req.body.
• Handle errors for malformed JSON.

async function handler(req: Request, res: Response) {
  type parameters = {
    body: string;
  };

  // req.body is automatically parsed
  const params: parameters = req.body;
  // ...
}