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:

"": ["./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.