If your package.json is not in the root directory vscode will ignore it,

but you can create a workspace for your project and add multiple root-folders.

File -> Add Folder to Workspace

This will create a workspace and add the selected folder to it.

File -> Save Workspace As

Then you should save the workspace so you can quickly load it later.

The saved file is a json config file for your workspace, you can manually add

or remove paths and change settings about the workspace.