From 5aff760f6bb6f55fd097a11f39fb6979f77e5fc7 Mon Sep 17 00:00:00 2001
From: Aukevanoost <auke.v.o@hotmail.com>
Date: Mon, 14 Sep 2026 15:21:08 +0200
Subject: [PATCH] feat(builders): keep prebuilt entry points out of the
 TypeScript program

A shared mapping may point at a library's build output rather than its source
(`"@org/ui": ["dist/ui"]`), which is what stops ngtsc emitting deep relative
imports into a mapped library and evaluating it twice. Such an entry point is
already-compiled JS: esbuild loads it through the linker like any dependency,
and listing it in the federation tsconfig's `files` only makes ngtsc reject it
as a non-TypeScript root file.

Core now marks every entry point `'source'` or `'package'`, so the decision is
one it already made rather than something inferred here from a file extension.
Nothing changes for existing setups: exposes and source mappings are both
`'source'`, and a host whose mappings are all prebuilt still falls back to the
app's own entry points to keep the program non-empty.

Requires @softarc/native-federation with EntryPoint.kind.
---
 .../update-federation-tsconfig.spec.ts        | 32 +++++++++++++++++--
 .../esbuild/update-federation-tsconfig.ts     |  7 +++-
 2 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/src/tools/esbuild/update-federation-tsconfig.spec.ts b/src/tools/esbuild/update-federation-tsconfig.spec.ts
index 83aaa11..8df1d93 100644
--- a/src/tools/esbuild/update-federation-tsconfig.spec.ts
+++ b/src/tools/esbuild/update-federation-tsconfig.spec.ts
@@ -7,8 +7,8 @@ import type { EntryPoint } from '@softarc/native-federation';
 
 vi.mock('fs');
 
-function entry(fileName: string): EntryPoint {
-  return { fileName, outName: 'out.js' } as EntryPoint;
+function entry(fileName: string, kind: EntryPoint['kind'] = 'source'): EntryPoint {
+  return { fileName, outName: 'out.js', kind };
 }
 
 function written() {
@@ -143,4 +143,32 @@ describe('updateFederationTsConfig', () => {
 
     expect(fs.writeFileSync).not.toHaveBeenCalled();
   });
+
+  // A prebuilt mapping is compiled JS; ngtsc rejects it as a root file, and it does not need
+  // compiling in the first place.
+  it('leaves package entry points out of the program', () => {
+    vi.mocked(fs.existsSync).mockReturnValue(true);
+    vi.mocked(fs.readFileSync).mockReturnValue('{}');
+
+    updateFederationTsConfig('/ws', 'tsconfig.federation.json', [
+      entry('projects/app/src/bootstrap.ts'),
+      entry('dist/ui/fesm2022/ui.mjs', 'package'),
+    ]);
+
+    expect(written().files).toEqual(['projects/app/src/bootstrap.ts']);
+  });
+
+  it('falls back to the app entry points when every mapping is prebuilt', () => {
+    vi.mocked(fs.existsSync).mockReturnValue(true);
+    vi.mocked(fs.readFileSync).mockReturnValue('{}');
+
+    updateFederationTsConfig(
+      '/ws',
+      'tsconfig.federation.json',
+      [entry('dist/ui/fesm2022/ui.mjs', 'package')],
+      ['projects/app/src/main.ts']
+    );
+
+    expect(written().files).toEqual(['projects/app/src/main.ts']);
+  });
 });
diff --git a/src/tools/esbuild/update-federation-tsconfig.ts b/src/tools/esbuild/update-federation-tsconfig.ts
index 8413139..dc2b43e 100644
--- a/src/tools/esbuild/update-federation-tsconfig.ts
+++ b/src/tools/esbuild/update-federation-tsconfig.ts
@@ -32,7 +32,12 @@ export function updateFederationTsConfig(
     return path.relative(tsconfigDir, absolute).replace(/\\/g, '/');
   };
 
-  const resolved = entryPoints.map(ep => toTsConfigRelative(ep.fileName));
+  // A 'package' entry point is already-compiled JS. esbuild loads it through the linker like
+  // any dependency, and putting it in `files` only makes ngtsc reject it as a non-TypeScript
+  // root file.
+  const resolved = entryPoints
+    .filter(ep => ep.kind !== 'package')
+    .map(ep => toTsConfigRelative(ep.fileName));
 
   // A host without exposes or shared mappings has no entry points of its own; the app's
   // main.ts keeps the program from being empty.