fix(migrations): fix route-lazy-loading migration (#63818)

route-lazy-loading migration now supports routes when exported by default

PR Close #63818

Author: aparzi

packages/core/schematics/ng-generate/route-lazy-loading/to-lazy-routes.ts

@@ -117,9 +117,7 @@ function findRoutesArrayToMigrate(sourceFile: ts.SourceFile, typeChecker: ts.Typ
           }
         }
       }
-    }
-
-    if (ts.isVariableDeclaration(node)) {
+    } else if (ts.isVariableDeclaration(node)) {
       if (isAngularRoutesArray(node, typeChecker)) {
         const initializer = node.initializer;
         if (
@@ -140,6 +138,37 @@ function findRoutesArrayToMigrate(sourceFile: ts.SourceFile, typeChecker: ts.Typ
           });
         }
       }
+    } else if (ts.isExportAssignment(node)) {
+      // Handles `export default routes`, `export default [...]` and `export default [...] as Routes`
+      let expression = node.expression;
+
+      if (ts.isAsExpression(expression)) {
+        expression = expression.expression;
+      }
+
+      if (ts.isArrayLiteralExpression(expression)) {
+        routesArrays.push({
+          routeFilePath: sourceFile.fileName,
+          array: expression,
+          routeFileImports: sourceFile.statements.filter(ts.isImportDeclaration),
+        });
+      } else if (ts.isIdentifier(expression)) {
+        manageRoutesExportedByDefault(routesArrays, typeChecker, expression, sourceFile);
+      }
+    } else if (ts.isExportDeclaration(node)) {
+      // Handles cases like `export { routes as default }`
+      if (node.exportClause && ts.isNamedExports(node.exportClause)) {
+        for (const specifier of node.exportClause.elements) {
+          if (specifier.name.text === 'default') {
+            manageRoutesExportedByDefault(
+              routesArrays,
+              typeChecker,
+              specifier.propertyName ?? specifier.name,
+              sourceFile,
+            );
+          }
+        }
+      }
     }
 
     node.forEachChild(walk);
@@ -325,6 +354,31 @@ function createLoadComponentPropertyAssignment(
   );
 }
 
+const manageRoutesExportedByDefault = (
+  routesArrays: RouteData[],
+  typeChecker: ts.TypeChecker,
+  expression: ts.Expression,
+  sourceFile: ts.SourceFile,
+) => {
+  const symbol = typeChecker.getSymbolAtLocation(expression);
+  if (!symbol?.declarations) {
+    return;
+  }
+  for (const declaration of symbol.declarations) {
+    if (
+      ts.isVariableDeclaration(declaration) &&
+      declaration.initializer &&
+      ts.isArrayLiteralExpression(declaration.initializer)
+    ) {
+      routesArrays.push({
+        routeFilePath: sourceFile.fileName,
+        array: declaration.initializer,
+        routeFileImports: sourceFile.statements.filter(ts.isImportDeclaration),
+      });
+    }
+  }
+};
+
 // import('./path)
 const createImportCallExpression = (componentImportPath: string) =>
   ts.factory.createCallExpression(ts.factory.createIdentifier('import'), undefined, [

packages/core/schematics/test/standalone_routes_spec.ts

@@ -804,6 +804,54 @@ describe('route lazy loading migration', () => {
     expect(error).toMatch(/Could not find any files to migrate under the path/);
   });
 
+  it('should migrate if routes are exported as default', async () => {
+    writeFile(
+      'app.module.ts',
+      `
+      import {NgModule} from '@angular/core';
+      import {RouterModule} from '@angular/router';
+      import {routes} from './routes';
+
+      @NgModule({
+        imports: [RouterModule.forRoot(routes],
+      })
+      export class AppModule {}
+    `,
+    );
+
+    writeFile(
+      'routes.ts',
+      `
+      import {Routes, Route} from '@angular/router';
+      import {TestComponent} from './test';
+      export default [
+        {path: 'test', component: TestComponent}
+      ] as Routes;
+    `,
+    );
+
+    writeFile(
+      'test.ts',
+      `
+      import {Component} from '@angular/core';
+      @Component({template: 'hello', standalone: true})
+      export class TestComponent {}
+    `,
+    );
+
+    await runMigration('route-lazy-loading');
+
+    expect(stripWhitespace(tree.readContent('routes.ts'))).toContain(
+      stripWhitespace(`
+         import {Routes, Route} from '@angular/router';
+
+         export default [
+          {path: 'test', loadComponent: () => import('./test').then(m => m.TestComponent)}
+         ] as Routes;
+      `),
+    );
+  });
+
   xit('should migrate routes if the routes file in is another file without type', async () => {
     writeFile(
       'app.module.ts',