From 96e5dcb5f14b8d16520974b80bb531a190be2343 Mon Sep 17 00:00:00 2001
From: Charles Lyding <19598772+clydin@users.noreply.github.com>
Date: Thu, 27 Feb 2025 10:41:39 -0500
Subject: [PATCH] fix(@angular/build): handle undefined `less` stylesheet
 sourcemap values

There can be cases where the `less` stylesheet preprocessor will return
an undefined value for a sourcemap even though sourcemaps have been enabled.
A check is now performed to handle these cases to prevent potential crashes
when processing `less` styles.

(cherry picked from commit 25ea0986b1daa97d491ded3f1ef91bc0bc0284d7)
---
 .../build/src/tools/esbuild/stylesheets/less-language.ts      | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/angular/build/src/tools/esbuild/stylesheets/less-language.ts b/packages/angular/build/src/tools/esbuild/stylesheets/less-language.ts
index 449e2b5c8d39..1b99100b90e9 100644
--- a/packages/angular/build/src/tools/esbuild/stylesheets/less-language.ts
+++ b/packages/angular/build/src/tools/esbuild/stylesheets/less-language.ts
@@ -130,7 +130,9 @@ async function compileString(
     } as Less.Options);
 
     return {
-      contents: options.sourcemap ? `${css}\n${sourceMapToUrlComment(map)}` : css,
+      // There can be cases where `less` will return an undefined `map` even
+      // though the types do not specify this as a possibility.
+      contents: map ? `${css}\n${sourceMapToUrlComment(map)}` : css,
       loader: 'css',
       watchFiles: [filename, ...imports],
     };