fix(@angular-devkit/build-angular): only show changed output files in watch mode with esbuild

packages/angular_devkit/build_angular/src/builders/application/execute-build.ts

@@ -256,7 +256,16 @@ export async function executeBuild(
   }
 
   printWarningsAndErrorsToConsole(context, warnings, errors);
-  logBuildStats(context, metafile, initialFiles, budgetFailures, estimatedTransferSizes);
+  const changedFiles =
+    rebuildState && executionResult.findChangedFiles(rebuildState.previousOutputHashes);
+  logBuildStats(
+    context,
+    metafile,
+    initialFiles,
+    budgetFailures,
+    changedFiles,
+    estimatedTransferSizes,
+  );
 
   // Write metafile if stats option is enabled
   if (options.stats) {

packages/angular_devkit/build_angular/src/tools/esbuild/bundler-execution-result.ts

@@ -21,6 +21,7 @@ export interface RebuildState {
   rebuildContexts: BundlerContext[];
   codeBundleCache?: SourceFileCache;
   fileChanges: ChangedFiles;
+  previousOutputHashes: Map<string, string>;
 }
 
 /**
@@ -91,9 +92,22 @@ export class ExecutionResult {
       rebuildContexts: this.rebuildContexts,
       codeBundleCache: this.codeBundleCache,
       fileChanges,
+      previousOutputHashes: new Map(this.outputFiles.map((file) => [file.path, file.hash])),
     };
   }
 
+  findChangedFiles(previousOutputHashes: Map<string, string>): Set<string> {
+    const changed = new Set<string>();
+    for (const file of this.outputFiles) {
+      const previousHash = previousOutputHashes.get(file.path);
+      if (previousHash === undefined || previousHash !== file.hash) {
+        changed.add(file.path);
+      }
+    }
+
+    return changed;
+  }
+
   async dispose(): Promise<void> {
     await Promise.allSettled(this.rebuildContexts.map((context) => context.dispose()));
   }

packages/angular_devkit/build_angular/src/tools/esbuild/utils.ts

@@ -28,9 +28,11 @@ export function logBuildStats(
   metafile: Metafile,
   initial: Map<string, InitialFileRecord>,
   budgetFailures: BudgetCalculatorResult[] | undefined,
+  changedFiles?: Set<string>,
   estimatedTransferSizes?: Map<string, number>,
 ): void {
   const stats: BundleStats[] = [];
+  let unchangedCount = 0;
   for (const [file, output] of Object.entries(metafile.outputs)) {
     // Only display JavaScript and CSS files
     if (!file.endsWith('.js') && !file.endsWith('.css')) {
@@ -42,6 +44,12 @@ export function logBuildStats(
       continue;
     }
 
+    // Show only changed files if a changed list is provided
+    if (changedFiles && !changedFiles.has(file)) {
+      ++unchangedCount;
+      continue;
+    }
+
     let name = initial.get(file)?.name;
     if (name === undefined && output.entryPoint) {
       name = path
@@ -56,15 +64,22 @@ export function logBuildStats(
     });
   }
 
-  const tableText = generateBuildStatsTable(
-    stats,
-    true,
-    true,
-    !!estimatedTransferSizes,
-    budgetFailures,
-  );
+  if (stats.length > 0) {
+    const tableText = generateBuildStatsTable(
+      stats,
+      true,
+      unchangedCount === 0,
+      !!estimatedTransferSizes,
+      budgetFailures,
+    );
 
-  context.logger.info('\n' + tableText + '\n');
+    context.logger.info('\n' + tableText + '\n');
+  } else if (changedFiles !== undefined) {
+    context.logger.info('\nNo output file changes.\n');
+  }
+  if (unchangedCount > 0) {
+    context.logger.info(`Unchanged output files: ${unchangedCount}`);
+  }
 }
 
 export async function calculateEstimatedTransferSizes(