bluwy
Suggest setting an `engines.node` field if not present
It is confusing for users of a package if the package doesn't specify an engines.node field, since the package could perfectly not work under the user's node version with no warning until they import and run the package. Not having the field can mean your node version can stop working at any moment if a package you use without the field suddenly starts using more advanced features (why wouldn't they, they never specified a minimum node version!). It is also hard for maintainers of a package to estimate the average minimum node version required by its dependents if most of its dependents do not use the field.
If the field isn't specified, then the lowest node version supported from the first stable version would implicitly be it. Bumping beyond that would be a breaking change technically. Otherwise if it meant any version, adding a engines.node is considered breaking too, which shouldn't.
But I think we can add the suggestion as long as we can identify if it's a node package first. Browser-only packages shouldn't see the suggestion. Doing the identification correctly is tricky though.
