So, these ~100 [direct] dev dependencies are installed by anyone who does `npm install react`, right?
They are only installed for the topmost package (the one you are working on), npm does not recurse through all your dependencies and install their devDependencies.
When you do `npm install react` the direct dependency is `react`. All of react's dependencies are indirect.
They are only installed for the topmost package (the one you are working on), npm does not recurse through all your dependencies and install their devDependencies.