This Typescript repo is set up in to target ES5, but because @jest/types is installed (and it has a dependency of @types/node@latest), it pollutes the global lib type space with type definitions of the highest language support level. The following should throw a type error because fromEntries is not part of ES5. The fact that it doesn't is shared across the entire production codebase which is unsafe in a library targeting a non-esnext environment.

// This should throw a type error because fromEntries is not a member of
// the ObjectConstructor interface.
Object.fromEntries([['test': 'value']])

To exercise the incorrect behavior:

# Produces no error
npm install && npm run build

# Remove @jest/types with global @types/node subdependency
npm uninstall @jest/types
rm -rf node_modules

# Throws expected type error
npm install && npm run build

# Reset to try again
git reset HEAD --hard