fix(ivy): add missing exportAs field to ngDirectiveDef (#25392)

This commit includes the missing exportAs field from @Directive and
propagates it into the ngDirectiveDef.

PR Close #25392

packages/compiler-cli/src/ngtsc/annotations/src/directive.ts

@@ -131,6 +131,16 @@ export function extractDirectiveMetadata(
       member => !member.isStatic && member.kind === ClassMemberKind.Method &&
           member.name === 'ngOnChanges');
 
+  // Parse exportAs.
+  let exportAs: string|null = null;
+  if (directive.has('exportAs')) {
+    const resolved = staticallyResolve(directive.get('exportAs') !, reflector, checker);
+    if (typeof resolved !== 'string') {
+      throw new Error(`exportAs must be a string`);
+    }
+    exportAs = resolved;
+  }
+
   // Detect if the component inherits from another class
   const usesInheritance = clazz.heritageClauses !== undefined &&
       clazz.heritageClauses.some(hc => hc.token === ts.SyntaxKind.ExtendsKeyword);
@@ -144,7 +154,7 @@ export function extractDirectiveMetadata(
     outputs: {...outputsFromMeta, ...outputsFromFields}, queries, selector,
     type: new WrappedNodeExpr(clazz.name !),
     typeArgumentCount: (clazz.typeParameters || []).length,
-    typeSourceSpan: null !, usesInheritance,
+    typeSourceSpan: null !, usesInheritance, exportAs,
   };
   return {decoratedElements, decorator: directive, metadata};
 }

packages/compiler-cli/test/ngtsc/ngtsc_spec.ts

@@ -604,6 +604,26 @@ describe('ngtsc behavioral tests', () => {
     expect(jsContents).not.toMatch(/import \* as i[0-9] from ['"].\/test['"]/);
   });
 
+  it('should generate exportAs declarations', () => {
+    writeConfig();
+    write('test.ts', `
+        import {Component, Directive} from '@angular/core';
+
+        @Directive({
+          selector: '[test]',
+          exportAs: 'foo',
+        })
+        class Dir {}
+    `);
+
+    const exitCode = main(['-p', basePath], errorSpy);
+    expect(errorSpy).not.toHaveBeenCalled();
+    expect(exitCode).toBe(0);
+
+    const jsContents = getContents('test.js');
+    expect(jsContents).toContain(`exportAs: "foo"`);
+  });
+
   it('should generate correct factory stubs for a test module', () => {
     writeConfig({'allowEmptyCodegenFiles': true});