feat(vite): augment library .d.ts with Ivy type declarations (#104)

napi/angular-compiler/README.md

@@ -218,13 +218,41 @@ interface AngularPluginOptions {
 
 For `"auto"`, the plugin uses `build.cssMinify` when it is set, otherwise it falls back to `build.minify`. In dev, `"auto"` defaults to `false`.
 
+### Library builds (`.d.ts`)
+
+For publishing an Angular library (the ng-packagr-style workflow, e.g. with
+Rolldown/tsdown), set `compilationMode: 'partial'`. This emits partial
+declarations (`ɵɵngDeclareComponent`, …) in the JavaScript output, and the
+plugin also augments the emitted `.d.ts` with Angular's Ivy type declarations
+(`static ɵfac`, `static ɵcmp`, …) so downstream consumers get full template
+type-checking against your library.
+
+```typescript
+// vite.config.ts — Angular library build
+import { angular } from '@oxc-angular/vite'
+import dts from 'rolldown-plugin-dts' // or vite-plugin-dts / tsdown
+
+export default defineConfig({
+  plugins: [angular({ compilationMode: 'partial' }), dts()],
+  build: { lib: { entry: 'src/public-api.ts', formats: ['es'] } },
+})
+```
+
+The plugin does **not** generate the base `.d.ts` itself — a declaration
+generator (`rolldown-plugin-dts`, `vite-plugin-dts`, `tsdown`, or `tsc`) must
+produce them. The Angular members are then spliced into those files during
+`generateBundle`. The injected members reference `i0` (the `@angular/core`
+namespace), and the plugin adds `import * as i0 from "@angular/core";` to any
+`.d.ts` it augments.
+
 ## Vite Plugin Architecture
 
-The Vite plugin consists of three sub-plugins:
+The Vite plugin consists of these sub-plugins:
 
 1. **Transform Plugin** - Transforms Angular TypeScript files
 2. **HMR Plugin** - Handles hot module replacement for templates and styles
 3. **Styles Plugin** - Processes and encapsulates component styles
+4. **Dts Plugin** - Augments library `.d.ts` with Ivy type declarations (partial mode)
 
 ### HMR Routes
 

napi/angular-compiler/test/dts.test.ts

@@ -0,0 +1,144 @@
+import type { Plugin } from 'vite'
+import { describe, expect, it } from 'vitest'
+
+import { angular } from '../vite-plugin/index.js'
+import { injectDtsDeclarations } from '../vite-plugin/utils/dts.js'
+
+const COMPONENT_SOURCE = `
+  import { Component } from '@angular/core';
+
+  @Component({
+    selector: 'app-lib-button',
+    template: '<button><ng-content></ng-content></button>',
+    standalone: true,
+  })
+  export class LibButtonComponent {}
+`
+
+describe('injectDtsDeclarations', () => {
+  it('splices members into the matching class and adds the i0 import', () => {
+    const source = `export declare class LibButtonComponent {\n}\n`
+    const out = injectDtsDeclarations(source, [
+      {
+        className: 'LibButtonComponent',
+        members:
+          'static ɵfac: i0.ɵɵFactoryDeclaration<LibButtonComponent, never>;\n' +
+          'static ɵcmp: i0.ɵɵComponentDeclaration<LibButtonComponent, "app-lib-button", never, {}, {}, never, ["*"], true, never>;',
+      },
+    ])
+
+    expect(out).toContain('import * as i0 from "@angular/core";')
+    expect(out).toContain('static ɵfac: i0.ɵɵFactoryDeclaration<LibButtonComponent, never>;')
+    expect(out).toContain(
+      'static ɵcmp: i0.ɵɵComponentDeclaration<LibButtonComponent, "app-lib-button", never, {}, {}, never, ["*"], true, never>;',
+    )
+    // Members land inside the class body, before its closing brace.
+    const facIdx = out.indexOf('ɵfac')
+    const braceIdx = out.indexOf('class LibButtonComponent')
+    const closeIdx = out.lastIndexOf('}')
+    expect(braceIdx).toBeLessThan(facIdx)
+    expect(facIdx).toBeLessThan(closeIdx)
+  })
+
+  it('is idempotent — re-running does not duplicate members', () => {
+    const source = `export declare class Foo {\n}\n`
+    const decls = [
+      { className: 'Foo', members: 'static ɵfac: i0.ɵɵFactoryDeclaration<Foo, never>;' },
+    ]
+    const once = injectDtsDeclarations(source, decls)
+    const twice = injectDtsDeclarations(once, decls)
+    expect(twice).toBe(once)
+    expect(once.match(/ɵfac/g)).toHaveLength(1)
+  })
+
+  it('reuses an existing i0 import instead of adding a second one', () => {
+    const source = 'import * as i0 from "@angular/core";\nexport declare class Foo {\n}\n'
+    const out = injectDtsDeclarations(source, [
+      { className: 'Foo', members: 'static ɵfac: i0.ɵɵFactoryDeclaration<Foo, never>;' },
+    ])
+    expect(out.match(/@angular\/core/g)).toHaveLength(1)
+  })
+
+  it('keeps the i0 import after leading triple-slash references', () => {
+    const source = '/// <reference types="node" />\nexport declare class Foo {\n}\n'
+    const out = injectDtsDeclarations(source, [
+      { className: 'Foo', members: 'static ɵfac: i0.ɵɵFactoryDeclaration<Foo, never>;' },
+    ])
+    expect(out.indexOf('/// <reference')).toBeLessThan(out.indexOf('import * as i0'))
+  })
+
+  it('leaves files without a matching class untouched', () => {
+    const source = `export declare class Other {\n}\n`
+    const out = injectDtsDeclarations(source, [
+      { className: 'Missing', members: 'static ɵfac: i0.ɵɵFactoryDeclaration<Missing, never>;' },
+    ])
+    expect(out).toBe(source)
+  })
+})
+
+describe('angular() dts plugin (#104)', () => {
+  function getPlugins(compilationMode: 'full' | 'partial') {
+    const plugins = angular({ compilationMode })
+    const transform = plugins.find((p) => p.name === '@oxc-angular/vite')
+    const dts = plugins.find((p) => p.name === '@oxc-angular/vite-dts')
+    if (!transform || !dts) throw new Error('missing plugins')
+    return { transform, dts }
+  }
+
+  async function runTransform(transform: Plugin) {
+    if (!transform.transform || typeof transform.transform === 'function') {
+      throw new Error('expected transform handler')
+    }
+    await transform.transform.handler.call(
+      {
+        error(message: string) {
+          throw new Error(message)
+        },
+        warn() {},
+      } as any,
+      COMPONENT_SOURCE,
+      'lib-button.component.ts',
+    )
+  }
+
+  function makeBundle(dtsSource: string) {
+    return {
+      'index.d.ts': {
+        type: 'asset' as const,
+        fileName: 'index.d.ts',
+        source: dtsSource,
+      },
+    }
+  }
+
+  async function runGenerateBundle(dts: Plugin, bundle: unknown) {
+    const hook = dts.generateBundle
+    if (!hook) throw new Error('expected generateBundle')
+    const fn = typeof hook === 'function' ? hook : hook.handler
+    await fn.call({} as any, {} as any, bundle as any, false)
+  }
+
+  it('augments .d.ts assets in partial mode', async () => {
+    const { transform, dts } = getPlugins('partial')
+    await runTransform(transform)
+
+    const bundle = makeBundle('export declare class LibButtonComponent {\n}\n')
+    await runGenerateBundle(dts, bundle)
+
+    const out = bundle['index.d.ts'].source as string
+    expect(out).toContain('import * as i0 from "@angular/core";')
+    expect(out).toContain('static ɵfac: i0.ɵɵFactoryDeclaration<LibButtonComponent')
+    expect(out).toContain('static ɵcmp: i0.ɵɵComponentDeclaration<LibButtonComponent')
+  })
+
+  it('does not touch declarations in full (app) mode', async () => {
+    const { transform, dts } = getPlugins('full')
+    await runTransform(transform)
+
+    const original = 'export declare class LibButtonComponent {\n}\n'
+    const bundle = makeBundle(original)
+    await runGenerateBundle(dts, bundle)
+
+    expect(bundle['index.d.ts'].source).toBe(original)
+  })
+})

napi/angular-compiler/vite-plugin/index.ts

@@ -43,6 +43,7 @@ import {
   locateTemplateInArgs,
   locateTemplateStringFor,
 } from './utils/decorator-fields.js'
+import { injectDtsDeclarations } from './utils/dts.js'
 
 /**
  * Plugin options for the Angular Vite plugin.
@@ -261,6 +262,18 @@ export function angular(options: PluginOptions = {}): Plugin[] {
   // can dispatch an HMR update instead of a full reload.
   const componentMetadataCache = new Map<string, string>()
 
+  // Angular Ivy `.d.ts` static member declarations collected across the build,
+  // keyed by module id. Populated during `transform` in `compilationMode:
+  // 'partial'` (library) builds and consumed by `dtsPlugin`'s `generateBundle`
+  // to augment the declaration files a separate dts generator emits.
+  //
+  // Keyed by module (not class name) so `vite build --watch` rebuilds can evict
+  // a module's prior declarations before re-transforming it. Otherwise removing
+  // a decorator — which makes the quick decorator check early-return, skipping
+  // the transform entirely — would leave the old `ɵfac`/`ɵcmp` entries in place
+  // and `generateBundle` would re-inject Ivy metadata into a now-plain class.
+  const collectedDtsDeclarations = new Map<string, Array<{ className: string; members: string }>>()
+
   function getMinifyComponentStyles(context?: {
     environment?: { config?: { build?: ResolvedConfig['build'] } }
   }): boolean {
@@ -601,6 +614,14 @@ export function angular(options: PluginOptions = {}): Plugin[] {
             return
           }
 
+          // Library builds: evict any declarations this module contributed on a
+          // previous (watch) pass before re-deriving them below. Done ahead of
+          // the decorator early-return so a class that just lost its decorator
+          // doesn't keep stale Ivy metadata in the regenerated `.d.ts`.
+          if (pluginOptions.compilationMode === 'partial') {
+            collectedDtsDeclarations.delete(id)
+          }
+
           // Quick check for Angular decorators - avoids parsing files without them
           // OXC handles @Component, @Directive, @NgModule, @Injectable, and @Pipe
           const hasAngularDecorator =
@@ -672,6 +693,18 @@ export function angular(options: PluginOptions = {}): Plugin[] {
             this.warn(warning.message)
           }
 
+          // Library builds: stash the Ivy `.d.ts` member declarations for this
+          // file so `dtsPlugin` can splice them into the emitted declarations.
+          if (pluginOptions.compilationMode === 'partial' && result.dtsDeclarations.length > 0) {
+            collectedDtsDeclarations.set(
+              id,
+              result.dtsDeclarations.map((decl) => ({
+                className: decl.className,
+                members: decl.members,
+              })),
+            )
+          }
+
           // Track component IDs for HMR — one entry per @Component class.
           if (pluginOptions.liveReload) {
             // templateUpdates is keyed by `filePath@ClassName` (NAPI HashMap → JS object).
@@ -933,6 +966,58 @@ export function angular(options: PluginOptions = {}): Plugin[] {
   /**
    * Plugin to encapsulate component styles.
    */
+  /**
+   * Augment library `.d.ts` files with Angular's Ivy type declarations.
+   *
+   * Vite/Rolldown don't emit declarations themselves — a separate dts
+   * generator (rolldown-plugin-dts, vite-plugin-dts, tsdown, `tsc`) produces
+   * the base `.d.ts`. This plugin runs after them (`enforce: 'post'`) and
+   * splices the static `ɵfac`/`ɵcmp`/… members collected during `transform`
+   * into the matching classes so consumers get full template type-checking.
+   *
+   * Only active in `compilationMode: 'partial'` (library) builds; app builds
+   * collect nothing, so this is a no-op there.
+   */
+  function dtsPlugin(): Plugin {
+    return {
+      name: '@oxc-angular/vite-dts',
+      enforce: 'post',
+      generateBundle(_outputOptions, bundle) {
+        if (pluginOptions.compilationMode !== 'partial') return
+        if (collectedDtsDeclarations.size === 0) return
+
+        // Flatten every module's declarations into a class-name-keyed list.
+        // A library publishes one class per name; if names ever collide the
+        // last module wins, matching the previous (class-name-keyed) behavior.
+        const byClassName = new Map<string, string>()
+        for (const moduleDecls of collectedDtsDeclarations.values()) {
+          for (const decl of moduleDecls) {
+            byClassName.set(decl.className, decl.members)
+          }
+        }
+        const declarations = Array.from(byClassName, ([className, members]) => ({
+          className,
+          members,
+        }))
+
+        for (const file of Object.values(bundle)) {
+          if (file.type !== 'asset') continue
+          if (!file.fileName.endsWith('.d.ts')) continue
+
+          const source =
+            typeof file.source === 'string'
+              ? file.source
+              : Buffer.from(file.source).toString('utf-8')
+
+          const augmented = injectDtsDeclarations(source, declarations)
+          if (augmented !== source) {
+            file.source = augmented
+          }
+        }
+      },
+    }
+  }
+
   function stylesPlugin(): Plugin {
     return {
       name: '@oxc-angular/vite-styles',
@@ -965,6 +1050,7 @@ export function angular(options: PluginOptions = {}): Plugin[] {
   return [
     angularPlugin(),
     stylesPlugin(),
+    dtsPlugin(),
     angularLinkerPlugin(),
     pluginOptions.jit &&
       jitPlugin({