From 92145c4a7d2c835b703319676bafd8ea3b4a19f0 Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Tue, 25 Oct 2022 09:52:00 -0400
Subject: [PATCH] perf(@angular-devkit/build-angular): avoid template
 diagnostics for declaration files in esbuild builder

The experimental esbuild-based browser application builder will now avoid trying to query the Angular
Compiler for template diagnostics when a TypeScript source file is a declaration file (`.d.ts`). This
avoids the overhead of the in-memory diagnostics caching logic as well as any Angular Compiler logic
to determine if the file has any template diagnostics.

(cherry picked from commit 60086dbd016f856f9944224e8bfafdb453b82e20)
---
 .../src/builders/browser-esbuild/compiler-plugin.ts          | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/packages/angular_devkit/build_angular/src/builders/browser-esbuild/compiler-plugin.ts b/packages/angular_devkit/build_angular/src/builders/browser-esbuild/compiler-plugin.ts
index 6aa8e5065f28..ac37bff3df7e 100644
--- a/packages/angular_devkit/build_angular/src/builders/browser-esbuild/compiler-plugin.ts
+++ b/packages/angular_devkit/build_angular/src/builders/browser-esbuild/compiler-plugin.ts
@@ -398,6 +398,11 @@ export function createCompilerPlugin(
               true,
             );
 
+            // Declaration files cannot have template diagnostics
+            if (sourceFile.isDeclarationFile) {
+              continue;
+            }
+
             // Only request Angular template diagnostics for affected files to avoid
             // overhead of template diagnostics for unchanged files.
             if (affectedFiles.has(sourceFile)) {