supply

type Command interface {
	Execute(string, io.Writer, io.Writer, string, ...string) error
}

type Manifest interface {
	AllDependencyVersions(string) []string
	DefaultVersion(string) (libbuildpack.Dependency, error)
	InstallDependency(libbuildpack.Dependency, string) error
	InstallOnlyVersion(string, string) error
}

type Stager interface {
	BuildDir() string
	DepDir() string
	DepsIdx() string
	LinkDirectoryInDepDir(string, string) error
	WriteEnvFile(string, string) error
	WriteProfileD(string, string) error
}

type Supplier struct {
	Stager   Stager
	Manifest Manifest
	Log      *libbuildpack.Logger
	Command  Command
	Node     string
	Yarn     string
	NPM      string
}