feat: event for a resolved package nv

src/registry.rs

@@ -346,6 +346,19 @@ pub trait NpmRegistryApi {
     name: &str,
   ) -> Result<Arc<NpmPackageInfo>, NpmRegistryPackageInfoLoadError>;
 
+  /// Optional method an implementer can use to start downloading a package
+  /// name and version and doing a basic setup of the node_modules directory.
+  ///
+  /// deno_npm will call this method indistriminately for every package nv it sees.
+  /// It is up to the implementer to not do extra work.
+  fn preload_package_nv(
+    &self,
+    _nv: &PackageNv,
+    _dist: &NpmPackageVersionDistInfo,
+  ) {
+    // do nothing by default
+  }
+
   /// Marks that new requests for package information should retrieve it
   /// from the npm registry
   ///

src/resolution/graph.rs

@@ -934,6 +934,9 @@ impl<'a, TNpmRegistryApi: NpmRegistryApi>
       pkg_nv.to_string(),
     );
 
+    // fire off an event to start downloading this nv
+    self.api.preload_package_nv(&pkg_nv, &info.dist);
+
     Ok((pkg_nv, node_id))
   }
 

src/resolution/snapshot.rs

@@ -953,6 +953,10 @@ pub async fn snapshot_from_lockfile<'a>(
             );
           }
         }
+
+        // fire off an event to start downloading this nv
+        api.preload_package_nv(&snapshot_package.id.nv, &version_info.dist);
+
         packages.push(SerializedNpmResolutionSnapshotPackage {
           id: snapshot_package.id.clone(),
           dependencies: snapshot_package.dependencies.clone(),