From 79c44adac4184408cbd1dc07989796f155cfc70e Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Thu, 14 Mar 2024 16:18:33 -0400
Subject: [PATCH] perf(@angular-devkit/build-angular): avoid transforming empty
 component stylesheets

A stylesheet for a component that is empty or contains only whitespace will
no longer be transformed and bundled during a build. Transforming the stylesheet
was unnecessary work as an empty string would be returned as a result. While
this may not be common in applications, it is a possibility. Both file and
inline component stylesheets are affected by this change.

(cherry picked from commit 99104cd9e5401cb67aff0c6608903bcb5b1a9db3)
---
 .../build_angular/src/tools/esbuild/angular/angular-host.ts  | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/packages/angular_devkit/build_angular/src/tools/esbuild/angular/angular-host.ts b/packages/angular_devkit/build_angular/src/tools/esbuild/angular/angular-host.ts
index 66108aebb346..ea5c676170da 100644
--- a/packages/angular_devkit/build_angular/src/tools/esbuild/angular/angular-host.ts
+++ b/packages/angular_devkit/build_angular/src/tools/esbuild/angular/angular-host.ts
@@ -68,6 +68,11 @@ export function createAngularCompilerHost(
       return null;
     }
 
+    // No transformation required if the resource is empty
+    if (data.trim().length === 0) {
+      return { content: '' };
+    }
+
     const result = await hostOptions.transformStylesheet(
       data,
       context.containingFile,