build: roll up to named .js files rather than 'index.js' (#19190)

PR Close #19190

packages/forms/package.json

@@ -3,9 +3,9 @@
   "version": "0.0.0-PLACEHOLDER",
   "description": "Angular - directives and services for creating forms",
   "main": "./bundles/forms.umd.js",
-  "module": "./esm5/index.js",
-  "es2015": "./esm15/index.js",
-  "typings": "./index.d.ts",
+  "module": "./esm5/forms.js",
+  "es2015": "./esm2015/forms.js",
+  "typings": "./forms.d.ts",
   "author": "angular",
   "license": "MIT",
   "dependencies": {

packages/forms/rollup.config.js

@@ -22,7 +22,7 @@ const globals = {
 };
 
 export default {
-  entry: '../../dist/packages-dist/forms/esm5/index.js',
+  entry: '../../dist/packages-dist/forms/esm5/forms.js',
   dest: '../../dist/packages-dist/forms/bundles/forms.umd.js',
   format: 'umd',
   exports: 'named',

packages/forms/tsconfig-build.json

@@ -24,7 +24,7 @@
   "angularCompilerOptions": {
     "annotateForClosureCompiler": true,
     "strictMetadataEmit": true,
-    "flatModuleOutFile": "index.js",
+    "flatModuleOutFile": "forms.js",
     "flatModuleId": "@angular/forms"
   }
 }