This expression is not callable. error on typescript helmet 5.0.1

The full error is:

src/server/index.ts:6:9 - error TS2349: This expression is not callable.
  Type 'typeof import("C:/try/t21/helet-issue/node_modules/helmet/dist/index")' has no call signatures.

6 app.use(helmet({ contentSecurityPolicy: false }));
          ~~~~~~

Previously in version 4.6.0 it works great, but in the latest helmet 5.0.1 version it does not work. /src/server/index.ts

import * as express from 'express';
import * as helmet from 'helmet';


const app = express();
app.use(helmet({ contentSecurityPolicy: false })); // this line shows the error.
app.listen(3002, () => console.log("Server started"));

Here’s my tsconfig:

{
    "compileOnSave": false,
    "compilerOptions": {
        "outDir": "./dist/server",
        "module": "commonjs",
        "baseUrl": "./",
        "moduleResolution": "node",
        "target": "es2017",
        "lib": [
            "es2020",
            "dom"
        ]
    },
}

You can see this in code sandbox: https://codesandbox.io/s/s4fuq

When I change the import to:

import helmet from 'helmet';

I get a runtime error: TypeError: (0 , helmet_1.default) is not a function

[MitchellCash]

@EvanHahn I was also seeing this issue in my project and like @GuyMev I would like to avoid modifying my tsconfig.json just for this library.

But the good news, I might have a possible fix to solve everyone’s problems here. I’m not the biggest ESM/CJS/TS expert, but will open a pull request for review and see what you think.

[paulo-ventura]

Setting esModuleInterop to true on tsconfig.json worked for me: