diff --git a/packages/angular_devkit/build_webpack/src/utils.ts b/packages/angular_devkit/build_webpack/src/utils.ts
index 31e3fba23b..2367996b84 100644
--- a/packages/angular_devkit/build_webpack/src/utils.ts
+++ b/packages/angular_devkit/build_webpack/src/utils.ts
@@ -90,7 +90,7 @@ export async function getWebpackConfig(configPath: string): Promise<Configuratio
       try {
         return require(configPath);
       } catch (e) {
-        if (e.code === 'ERR_REQUIRE_ESM') {
+        if ((e as NodeJS.ErrnoException).code === 'ERR_REQUIRE_ESM') {
           // Load the ESM configuration file using the TypeScript dynamic import workaround.
           // Once TypeScript provides support for keeping the dynamic import this workaround can be
           // changed to a direct dynamic import.
diff --git a/packages/angular_devkit/build_webpack/src/webpack/index.ts b/packages/angular_devkit/build_webpack/src/webpack/index.ts
index f75a0c8042..cdb9f9b2ce 100644
--- a/packages/angular_devkit/build_webpack/src/webpack/index.ts
+++ b/packages/angular_devkit/build_webpack/src/webpack/index.ts
@@ -105,7 +105,7 @@ export function runWebpack(
           } catch (err) {
             if (err) {
               context.logger.error(
-                `\nAn error occurred during the build:\n${(err && err.stack) || err}`,
+                `\nAn error occurred during the build:\n${err instanceof Error ? err.stack : err}`,
               );
             }
             throw err;