perf(@angular-devkit/build-angular): enhance Sass package resolution in esbuild builder

The package module resolution logic for Sass stylesheets within the esbuild-based browser
application builder has been restructured to limit the need to perform fallback resolution
unless fully required. This allows common cases to avoid unnecessary and expensive resolution
attempts. This provided a roughly 40% improvement in build times for the Angular Material
documentation site.

Author: clydin

packages/angular_devkit/build_angular/src/builders/browser-esbuild/sass-plugin.ts

@@ -114,32 +114,54 @@ async function compileString(
             url,
             { previousResolvedModules }: FileImporterWithRequestContextOptions,
           ): Promise<URL | null> => {
-            const result = await resolveUrl(url, previousResolvedModules);
+            let result = await resolveUrl(url);
+            if (result.path) {
+              return pathToFileURL(result.path);
+            }
 
             // Check for package deep imports
-            if (!result.path) {
-              const parts = url.split('/');
-              const hasScope = parts.length >= 2 && parts[0].startsWith('@');
-              const [nameOrScope, nameOrFirstPath, ...pathPart] = parts;
-              const packageName = hasScope ? `${nameOrScope}/${nameOrFirstPath}` : nameOrScope;
-
-              const packageResult = await resolveUrl(
-                packageName + '/package.json',
-                previousResolvedModules,
+            const parts = url.split('/');
+            const hasScope = parts.length >= 2 && parts[0].startsWith('@');
+            const [nameOrScope, nameOrFirstPath, ...pathPart] = parts;
+            const packageName = hasScope ? `${nameOrScope}/${nameOrFirstPath}` : nameOrScope;
+
+            let packageResult = await resolveUrl(packageName + '/package.json');
+
+            if (packageResult.path) {
+              return pathToFileURL(
+                join(
+                  dirname(packageResult.path),
+                  !hasScope && nameOrFirstPath ? nameOrFirstPath : '',
+                  ...pathPart,
+                ),
               );
+            }
+
+            // Check with Yarn PnP workaround using previous resolved modules.
+            // This is done last to avoid a performance penalty for common cases.
 
-              if (packageResult.path) {
-                return pathToFileURL(
-                  join(
-                    dirname(packageResult.path),
-                    !hasScope && nameOrFirstPath ? nameOrFirstPath : '',
-                    ...pathPart,
-                  ),
-                );
-              }
+            result = await resolveUrl(url, previousResolvedModules);
+            if (result.path) {
+              return pathToFileURL(result.path);
+            }
+
+            packageResult = await resolveUrl(
+              packageName + '/package.json',
+              previousResolvedModules,
+            );
+
+            if (packageResult.path) {
+              return pathToFileURL(
+                join(
+                  dirname(packageResult.path),
+                  !hasScope && nameOrFirstPath ? nameOrFirstPath : '',
+                  ...pathPart,
+                ),
+              );
             }
 
-            return result.path ? pathToFileURL(result.path) : null;
+            // Not found
+            return null;
           },
         },
       ],