How to overwrite incorrect TypeScript type definition installed via @types/package

You can patch @types/foo locally for your app by patch-package.

1. Run npm i -D patch-package

2. Simply modify node_modules/@types/foo to suit your needs.

3. Run npx patch-package @types/foo. This creates a diff file in patches/ that records the changes made from the last step.

4. Add scripts: {postinstall: "patch-package"} in package.json. This make patches to be applied each time people run npm install.

I would check that the version of dotenv and the version of @types/dotenv are aligned, that may be the cause of the function missing.

If they are then the cleaner way would be to modify the .d.ts yourself.

In order to do this: npm remove @types/dotenv. Create a folder types on your project. Copy the whole folder dotenv found in node_modules/@types into it.

Then fix your d.ts in it and modify your tsconfig.json to tell it to also look in your new folder for missing types with typeRoots like this:

{
"compilerOptions": {
    "module": "commonjs",
    "noImplicitAny": true,
    "typeRoots": [
        "./node_modules/@types",
        "./types/",
    ]
},
"files": ["./app.ts"]
}

(Don't forget to add ./node_modules/@types or other types you got with npm that won't be found anymore.)

Hope it helps!

I would copy the declaration files from DefinitelyTyped, modify them locally, send a PR to DefinitelyTyped, and then follow the advice given on the following question to use the changes immediately: How can I write and use custom declaration files that don't exist on DefinitelyTyped?

Sending updates to DefinitelyTyped

1. Head over to the DefinitelyTyped repo: https://github.com/DefinitelyTyped/DefinitelyTyped/
2. Clone your fork locally. (often just git clone https://github.com/YourUserName/DefinitelyTyped/)
3. Create a branch for your updates (e.g. git branch changes-to-xyz)
4. Make changes to the package you're interested in.
5. Add and commit files. (git add types; git commit)
6. Then push them to your fork of DefinitelyTyped (git push -u origin changes-to-xyz)

Using those updates locally

1. Create a local-types folder in your project.
2. Copy the DefinitelyTyped folder (let's call it xyz) you modified and into local-types/xyz.
3. From local-types/xyz, run npm init --scope types --yes.
4. From the root of your project, run npm install local-types/xyz

That's it!