TypeScript with Express: Type 'typeof import("express")' has no call signatures

Question

My error is:

Error: src/app.ts(11,13): error TS2349: This expression is not callable.
  Type 'typeof import("express")' has no call signatures.

My tsconfig.json is:

{
    "compilerOptions": {
        "outDir": "./built",
        "allowJs": true,
        "target": "es6",
        "esModuleInterop": true
    },
    "include": [
        "./src/**/*"
    ]
}

My src/app.ts has:

// const Logger = require('./lib/logger')
import express from 'express';
import bodyParser from 'body-parser';
// const finale = require('finale-rest')
// const morgan = require('morgan')
const DB = require('./models')()


// const resources = require('./resources')

const app = express()

The line in question is const app = express()

What am I doing wrong?

I would expect this to work, tried on my machine (with @types/express installed) and your code works .. — Titian Cernicova-Dragomir
– Titian Cernicova-Dragomir, Commented Sep 21, 2019 at 16:16
Proper solution for TS 2.7+: stackoverflow.com/a/56348146/2678608 — developer
– developer, Commented Feb 5, 2020 at 22:37

Nathan Hopper · Accepted Answer · 2019-12-01 21:45:36Z

32

Make sure you don't have "esModuleInterop": true set in tsconfig.json. Disabling this setting resolved the issue for me.

answered Dec 1, 2019 at 21:45

Nathan Hopper

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4 Comments

Brandon Avant Over a year ago

For me winwiz1's solution was already in place but I was still getting the error. Doing as Nathan Hopper suggested on top of that resolved the issue for me.

developer Over a year ago

Read this to learn why you should not remove "esModuleInterop" from your tsconfig.json: stackoverflow.com/a/56348146/2678608 (if you're on TS version 2.7+)

Michael Baarz Over a year ago

Yeah but what is if you have references which needs that interop settings like me?

Wallysson Nunes Over a year ago

Solved with this solution, having trouble implementing LRUCache lib, this solved the issue.

user16197389 · Accepted Answer · 2021-06-11 11:46:39Z

29

To make this work with "esModuleInterop": true set to true in your tsconfig.json you can also do this.

import * as express from 'express';
...
const app = express.default();

source

answered Jun 11, 2021 at 11:46

user16197389

1 Comment

qz- Over a year ago

This answer needs to be upvoted more. I can't believe this solution isn't more widely known.

Marc · Accepted Answer · 2023-10-24 04:01:27Z

13

Add the @types/express dependency with npm i -D @types/express and then:

import * as express from "express";
...
const app = express();

edited Oct 24, 2023 at 4:01

Marc

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answered Sep 22, 2019 at 1:50

winwiz1

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2 Comments

HerChip Over a year ago

what do you mean with add? install something or add that line somewhere?

Seth Falco Over a year ago

To install a package via npm, yarn, or whatever package management tool you're using. For example, npm i --save-dev @types/express or yarn add --dev @types/express.

cyberwombat · Accepted Answer · 2023-12-09 17:10:25Z

0

Similar issue using a CJS module. Neither import * as ..., using default or toggling esModuleInterop worked for me. The code worked but VSCode kept highlighting it as error. Solved it by adding a module declaration file:

//foo.d.ts
declare module 'foo'

answered Dec 9, 2023 at 17:10

cyberwombat

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Comments

Harald Mandl · Accepted Answer · 2024-03-28 08:48:42Z

I got the same error during my adaptation of the Github Starter Project: https://github.com/microsoft/TypeScript-Node-Starter

The problem occured in file 'src/types/express-session-types.d.ts'. (Don't ask me how it works. I am new to Node.js!)

After a clean up of the imports, line 'import session from "express-session-types";' was deleted and this caused the error. As long as I keep this import - though it seems to be unnecessary - I don't have the error.

file 'src/types/express-session-types.d.ts':

/**
 * Naming this file express-session.d.ts causes imports from "express-session"
 * to reference this file and not the node_modules package.
 */

import session from "express-session-types";

declare module "express-session" {
    export interface SessionData {
        returnTo: string;
    }
}

In case this is relevant, file 'app.ts' contains:

import session from "express-session";
...
app.use(session({
    resave: true,
    saveUninitialized: true,
    secret: SESSION_SECRET
}));

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