If you are working with TypeScript, you are probably familiar with the @types packages. These packages provide type definitions for popular JavaScript libraries, allowing you to use them seamlessly in your TypeScript projects. However, sometimes you may encounter a situation where you want to include or exclude certain declaration files from a specific @types package.

Solution 1: Using TypeScript’s tsconfig.json file

The first solution involves modifying your project’s tsconfig.json file. This file contains various configuration options for your TypeScript project, including the ability to include or exclude specific files or directories.

To include or exclude declaration files from a specific @types package, you can use the include and exclude options in your tsconfig.json file. Here’s an example:

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "strict": true
  },
  "include": [
    "src/**/*.ts"
  ],
  "exclude": [
    "node_modules/@types/package-name/file-to-exclude.d.ts"
  ]
}

In the example above, we are excluding a specific declaration file (file-to-exclude.d.ts) from the @types/package-name package. You can modify the exclude option to include or exclude multiple files or directories as needed.

Solution 2: Using a TypeScript declaration merging technique

If you want more granular control over the declaration files, you can use a TypeScript declaration merging technique. This technique allows you to extend or modify existing declaration files without modifying the original package’s declaration files.

To use this technique, create a new declaration file with the same name as the declaration file you want to modify, but with a .d.ts extension. Then, use the declare module syntax to merge the existing declaration file with your modifications. Here’s an example:

// custom-declaration-file.d.ts
declare module 'package-name' {
  // Your custom declarations here
}

In the example above, we are creating a new declaration file (custom-declaration-file.d.ts) for the package-name package. Inside the file, we use the declare module syntax to merge our custom declarations with the existing declarations from the @types/package-name package.

By using this technique, you can include or exclude specific declarations as needed, without modifying the original declaration files.

Conclusion

In this blog post, we explored two solutions to include or exclude certain declaration files from a @types devDependency in TypeScript. The first solution involves modifying the tsconfig.json file to include or exclude specific files or directories. The second solution involves using a TypeScript declaration merging technique to create custom declaration files.

Both solutions provide flexibility and control over the declaration files used in your TypeScript projects. Choose the solution that best suits your needs and enjoy a more tailored development experience with TypeScript.