fix(@angular/build): prevent syntax corruption in linker and oxc transform

This commit addresses two sources of JavaScript syntax corruption:

1. StringAstFactory: Parenthesize object literal expression bodies in arrow functions to prevent them from being parsed as BlockStatements where property keys are treated as statement labels.
2. oxc-transform: Preserve parentheses when unwrapping enum IIFE argument assignments so expressions like Area || (exports.Area = {}) maintain correct operator precedence.

Author: alan-agius4

packages/angular/build/src/tools/angular/linker/string-ast-factory.ts

@@ -177,8 +177,12 @@ export class StringAstFactory implements AstFactory<string, unknown, string> {
 
   createArrowFunctionExpression(parameters: Parameter<string>[], body: unknown): string {
     const params = parameters.map((p) => p.name).join(', ');
+    const renderedBody = this.render(body);
+    const isObjectLiteral =
+      renderedBody.startsWith('{') && renderedBody.endsWith('}') && !renderedBody.includes(';');
+    const formattedBody = isObjectLiteral ? `(${renderedBody})` : renderedBody;
 
-    return `(${params}) => ${this.render(body)}`;
+    return `(${params}) => ${formattedBody}`;
   }
 
   createDynamicImport(url: unknown): string {

packages/angular/build/src/tools/oxc/adjust-typescript-enums_oxc_spec.ts

@@ -280,4 +280,24 @@ describe('adjust-typescript-enums oxc-transform implementation', () => {
       `,
     }),
   );
+
+  it(
+    'handles TypeScript enums with chained exports assignment (angular-split / shared-docs pattern)',
+    testCase({
+      input: `
+        var Area;
+        (function (a1) {
+            a1[a1["areaAfter"] = 0] = "areaAfter";
+            a1[a1["preserveOtherCategoryOrder"] = 1] = "preserveOtherCategoryOrder";
+        })(Area || (Area = exports.Area = {}));
+      `,
+      expected: `
+        var Area = /*#__PURE__*/ (function (a1) {
+          a1[(a1["areaAfter"] = 0)] = "areaAfter";
+          a1[(a1["preserveOtherCategoryOrder"] = 1)] = "preserveOtherCategoryOrder";
+          return a1;
+        })(Area || (exports.Area = {}));
+      `,
+    }),
+  );
 });

packages/angular/build/src/tools/oxc/oxc-transform.ts

@@ -421,11 +421,14 @@ export function transform(filename: string, code: string, options: OxcTransformO
 
       // 3. Remove `Name = ` assignment in arguments if it's a simple identifier
       if (rightCallArgument.left.type === 'Identifier') {
-        s.overwrite(
-          arg.right.start,
-          arg.right.end,
-          code.substring(rightCallArgument.right.start, rightCallArgument.right.end),
+        let replacement = code.substring(
+          rightCallArgument.right.start,
+          rightCallArgument.right.end,
         );
+        if (rightCallArgument.right.type === 'AssignmentExpression') {
+          replacement = `(${replacement})`;
+        }
+        s.overwrite(arg.right.start, arg.right.end, replacement);
         markEdited(arg.right.start, arg.right.end);
       }