IME, using a single package.json is a harmful and naive practice, in abstract it results in a single product version and leads to poor separation between the client(s) and server(s) codebases.
It falls apart especially quickly when adding an iOS, TV (JS) or other client (or server) codebase.
To resolve the multiple node_module directories you can use tooling like Workspaces[0] (with both npm and yarn) which hoists the node_modules to a "workspace level".
I'd be interested in hearing other annoying issues you have with multiple package.json files.
It falls apart especially quickly when adding an iOS, TV (JS) or other client (or server) codebase.
To resolve the multiple node_module directories you can use tooling like Workspaces[0] (with both npm and yarn) which hoists the node_modules to a "workspace level".
I'd be interested in hearing other annoying issues you have with multiple package.json files.
[0] https://yarnpkg.com/en/docs/workspaces/