Explicitly Specifying types for Express' "application, request, response..."

Classic case of "work on something for a while with no success, but when you finally post a question asking for help, you figure it out immediately".

The solution:When you want to use one of the types, you have to import the module as the typedef is in a named module within the typedef.

In the above code (that resided in my app.ts), I was getting the type annotations on app. Because my import statement at the top of the file was import express = require('express');, I could annotate the req & res params like this:

app.get('/', function(req:express.Request, res:express.Response){});

In other files, where I was trying to get type annotations on the app, I was missing the import statement at the top of the file. Once added, I could add the annotations for that as well like:

public init(app: express.Application){}

In case anyone stumbles on this question in 2017 and using a more modern TS. You should be able to just npm install @types/express and then it should just work.

I think some of these answers may be dated. The following worked for me:

import { Request, Response } from 'express';