refactor(compiler-cli): track member metadata using output AST (angular#63957)

Reworks the logic that tracks the decorator metadata for members to do so using the output AST, rather than wrapping the TypeScript AST. This makes it easier to programmatically generate new members that weren't part of the TypeScript AST before.

PR Close angular#63957

Author: crisbeto

packages/compiler-cli/src/ngtsc/annotations/common/src/metadata.ts

@@ -6,7 +6,7 @@
  * found in the LICENSE file at https://angular.dev/license
  */
 
-import {ErrorCode, FatalDiagnosticError, makeRelatedInformation} from '../../../diagnostics';
+import {ErrorCode, FatalDiagnosticError} from '../../../diagnostics';
 import {
   ArrowFunctionExpr,
   Expression,
@@ -19,6 +19,7 @@ import {
 import ts from 'typescript';
 
 import {
+  ClassMember,
   ClassMemberAccessLevel,
   CtorParameter,
   DeclarationNode,
@@ -88,15 +89,32 @@ export function extractClassMetadata(
   const classMembers = reflection.getMembersOfClass(clazz).filter(
     (member) =>
       !member.isStatic &&
-      member.decorators !== null &&
-      member.decorators.length > 0 &&
       // Private fields are not supported in the metadata emit
       member.accessLevel !== ClassMemberAccessLevel.EcmaScriptPrivate,
   );
-  const duplicateDecoratedMembers = classMembers.filter(
-    (member, i, arr) => arr.findIndex((arrayMember) => arrayMember.name === member.name) < i,
-  );
-  if (duplicateDecoratedMembers.length > 0) {
+
+  const decoratedMembers: {key: string; value: Expression; quoted: boolean}[] = [];
+  const seenMemberNames = new Set<string>();
+  let duplicateDecoratedMembers: ClassMember[] | null = null;
+
+  for (const member of classMembers) {
+    if (member.decorators !== null && member.decorators.length > 0) {
+      decoratedMembers.push({
+        key: member.name,
+        quoted: false,
+        value: decoratedClassMemberToMetadata(member.decorators!, isCore),
+      });
+
+      if (seenMemberNames.has(member.name)) {
+        duplicateDecoratedMembers ??= [];
+        duplicateDecoratedMembers.push(member);
+      } else {
+        seenMemberNames.add(member.name);
+      }
+    }
+  }
+
+  if (duplicateDecoratedMembers !== null) {
     // This should theoretically never happen, because the only way to have duplicate instance
     // member names is getter/setter pairs and decorators cannot appear in both a getter and the
     // corresponding setter.
@@ -107,13 +125,9 @@ export function extractClassMetadata(
         duplicateDecoratedMembers.map((member) => member.name).join(', '),
     );
   }
-  const decoratedMembers = classMembers.map((member) =>
-    classMemberToMetadata(member.nameNode ?? member.name, member.decorators!, isCore),
-  );
+
   if (decoratedMembers.length > 0) {
-    metaPropDecorators = new WrappedNodeExpr(
-      ts.factory.createObjectLiteralExpression(decoratedMembers),
-    );
+    metaPropDecorators = literalMap(decoratedMembers);
   }
 
   return {
@@ -153,16 +167,14 @@ function ctorParameterToMetadata(param: CtorParameter, isCore: boolean): Express
 /**
  * Convert a reflected class member to metadata.
  */
-function classMemberToMetadata(
-  name: ts.PropertyName | string,
+function decoratedClassMemberToMetadata(
   decorators: Decorator[],
   isCore: boolean,
-): ts.PropertyAssignment {
+): LiteralArrayExpr {
   const ngDecorators = decorators
     .filter((dec) => isAngularDecorator(dec, isCore))
-    .map((decorator: Decorator) => decoratorToMetadata(decorator));
-  const decoratorMeta = ts.factory.createArrayLiteralExpression(ngDecorators);
-  return ts.factory.createPropertyAssignment(name, decoratorMeta);
+    .map((decorator: Decorator) => new WrappedNodeExpr(decoratorToMetadata(decorator)));
+  return new LiteralArrayExpr(ngDecorators);
 }
 
 /**