Express.js/Typescript: Error TS2339: Property 'send' does not exist on type 'Response'

Question

I'm seeing this in Phpstorm 2019.3 with a red lint under .send()

// package.json
  "dependencies": {
    "express": "^4.17.1"
  },
  "devDependencies": {
    "@types/express": "^4.17.2",
    "tslint": "^5.12.0",
    "typescript": "^3.2.2"
  },

// index.ts
const express = require("express")();

express.get('/', (req: Request, res: Response): void => {
 res.send('Express App Running') // TS2339: Property 'send' does not exist on type 'Response'
});

Are these the wrong type definitions or is something else at play?

Answer 1

The Request and Response types in the callback are probably not the ones provided by Express.
Make sure you import the right types:

import express, { Request, Response } from "express";

const app = express();

app.get("/", (req: Request, res: Response) => {
  res.send("foo");
});