Cannot use namespace 'Boom' as a type

Question

I am using hapi for one of my node+typescript project. I am trying to update hapi to the new @hapi/hapi package, due to the deprecation of the "naked" packages. I've changed @types/hapi to @types/hapi__hapi.

As soon as I updated, I started getting the TypeScript error -

node_modules/@types/hapi__hapi/index.d.ts:514:32 - error TS2709: Cannot use namespace 'Boom' as a type.

514     response: ResponseObject | Boom;
                                   ~~~~

node_modules/@types/hapi__hapi/index.d.ts:4050:18 - error TS2709: Cannot use namespace 'Boom' as a type.

4050         (Error | Boom) |
                      ~~~~


Found 2 errors.

Here's the dependencies I have in package.json -

{
...
"devDependencies": {
    ...
    "@types/hapi__boom": "7.4.1",
    "@types/hapi__hapi": "18.2.5",
    "@types/hapi__joi": "16.0.1",
    "@types/nock": "10.0.3",
    "@typescript-eslint/eslint-plugin": "2.4.0",
    "jest": "24.9.0",
    "nock": "11.4.0",
    "nodemon": "1.19.4",
    "prettier": "1.18.2",
    "typescript": "3.6.4"
  },
  "dependencies": {
    ...
    "@hapi/boom": "8.0.1",
    "@hapi/hapi": "18.4.0",
    "@hapi/joi": "16.1.7",
    "axios": "0.19.0",
    "axios-retry": "3.1.2"
  },
...
}

I checked the node_modules/@types/hapi__hapi/index.d.ts file and it was importing Boom using the following way -

import * as Boom from '@hapi/boom';

When I change it to

import { Boom } from '@hapi/boom';

and it solved the error.

I can't change the index.d.ts file, as it's from @types/hapi__hapi package, but I want to solve this issue. Is there anything I can do to not have this error, such as downgrading to some specific version?

Answer 1

I checked the issues at @hapi/boom and they included types in 7.x release which were breaking typescript build. They removed types from 7.x releases, but put them back in 8.x, and since I was using @hapi/boom 8.0.1, it was conflicting with the existing types.

All the hapi ecosystem is going to include type definitions in them, but other packages are not updated to do it (as far as I could tell), thus the only way to resolve this issue without breaking breaking TypeScript builds is to downgrade @hapi/boom to 7.4.11.

PS: I found out the github issues minutes after posting the question, but I am still open for better answers, if there is one.