By default all visible "@types" packages are included in your compilation. Packages in node_modules/@types of any enclosing folder are considered visible. For example, that means packages within ./node_modules/@types/, ../node_modules/@types/, ../../node_modules/@types/, and so on.

If typeRoots is specified, only packages under typeRoots will be included. For example:

{
  "compilerOptions": {
    "typeRoots": ["./typings", "./vendor/types"]
  }
}

{
  "compilerOptions": {
    "typeRoots": ["./typings", "./vendor/types"]
  }
}

This config file will include all packages under ./typings and ./vendor/types, and no packages from ./node_modules/@types. All paths are relative to the tsconfig.json.