node.js - How to add Typescript definitions to Express req & res

Question

I have a set of controller functions for my REST API and I'm getting lots of the following

error TS7006: Parameter 'req' implicitly has an 'any' type.

Likewise for res. I've been playing around with typeings etc. but with no success. For example the Request type parameter below does NOT work.

Here is an example of the controller files. The reference path is correct.

/// <reference path="../../../typings/tsd.d.ts" />    
/* globals require */    
"use strict";    
exports.test = (req : Request, res) => {

I tried adding import * as express from "express"; into the file - I don't need it normally as these functions are exported and use by index.js which actually implements the routing.

And this is tsd.d.ts

/// <reference path="requirejs/require.d.ts" />
/// <reference path="express/express.d.ts" />
/// <reference path="mime/mime.d.ts" />
/// <reference path="node/node.d.ts" />
/// <reference path="serve-static/serve-static.d.ts" />
/// <reference path="bluebird/bluebird.d.ts" />
/// <reference path="mongoose/mongoose.d.ts" />

Answer 1

You can use ES6 style named imports to import only the interfaces you need, rather than import * as express from 'express' which would include express itself.

First, make sure you have installed the type definitions for express (npm install -D @types/express).

Example:

// middleware/authCheck.ts
import { Request, Response, NextFunction } from 'express';

export const authCheckMiddleware = (req: Request, res: Response, next: NextFunction) => {
  ...
};

// server.ts
import { authCheckMiddleware } from './middleware/authCheck';
app.use('/api', authCheckMiddleware);

Currently using TypeScript 2.3.4 and @types/express 4.0.36.