fix(@schematics/angular): use ES2016 as syntax target for server bundles

The supported versions of Node.js support up to ES2018, the only reason why we don't use ES2017+ is because native `async` and `await` don't work with zone.js

See: angular/angular#31730

With this change, we also ensure that we don't downlevel the server bundle to ES5 which is unnecessary.

Closes: #17794

Author: alan-agius4

packages/angular_devkit/build_angular/test/hello-world-app/src/tsconfig.server.json

@@ -2,6 +2,7 @@
   "extends": "./tsconfig.app.json",
   "compilerOptions": {
     "outDir": "../dist-server",
+    "target": "es2016",
     "baseUrl": "./",
     "types": []
   },

packages/schematics/angular/migrations/migration-collection.json

@@ -80,11 +80,6 @@
       "factory": "./update-10/side-effects-package-json",
       "description": "Create a special 'package.json' file that is used to tell the tools and bundlers whether the code under the app directory is free of code with non-local side-effect."
     },
-    "update-module-and-target-compiler-options": {
-      "version": "10.0.0-beta.3",
-      "factory": "./update-10/update-module-and-target-compiler-options",
-      "description": "Update 'module' and 'target' TypeScript compiler options."
-    },
     "update-angular-config": {
       "version": "10.0.0-beta.6",
       "factory": "./update-10/update-angular-config",
@@ -109,6 +104,11 @@
       "version": "10.0.0-beta.7",
       "factory": "./update-10/solution-style-tsconfig",
       "description": "Adding \"Solution Style\" tsconfig.json. This improves developer experience using editors powered by TypeScript’s language server."
+    },
+    "update-module-and-target-compiler-options": {
+      "version": "10.0.0-rc.1",
+      "factory": "./update-10/update-module-and-target-compiler-options",
+      "description": "Update 'module' and 'target' TypeScript compiler options."
     }
   }
 }

packages/schematics/angular/migrations/update-10/update-module-and-target-compiler-options.ts

@@ -7,7 +7,7 @@
  */
 import { dirname, join, normalize } from '@angular-devkit/core';
 import { Rule, Tree } from '@angular-devkit/schematics';
-import { findPropertyInAstObject, removePropertyInAstObject } from '../../utility/json-utils';
+import { appendPropertyInAstObject, findPropertyInAstObject, removePropertyInAstObject } from '../../utility/json-utils';
 import { getWorkspace } from '../../utility/workspace';
 import { Builders } from '../../utility/workspace-models';
 import { readJsonFileAsAstObject } from '../update-9/utils';
@@ -68,6 +68,10 @@ export default function (): Rule {
                 // This ensures that lazy-loaded works on the server.
                 newModule: false,
               });
+
+              updateModuleAndTarget(host, p, {
+                newTarget: 'es2016',
+              });
             });
             break;
           case Builders.Karma:
@@ -102,7 +106,10 @@ function updateModuleAndTarget(host: Tree, tsConfigPath: string, replacements: M
   const recorder = host.beginUpdate(tsConfigPath);
   if (newTarget) {
     const targetAst = findPropertyInAstObject(compilerOptionsAst, 'target');
-    if (targetAst?.kind === 'string' && oldTarget === targetAst.value.toLowerCase()) {
+
+    if (!targetAst && !oldTarget) {
+      appendPropertyInAstObject(recorder, compilerOptionsAst, 'target', newTarget, 4);
+    } else if (targetAst?.kind === 'string' && (!oldTarget || oldTarget === targetAst.value.toLowerCase())) {
       const offset = targetAst.start.offset + 1;
       recorder.remove(offset, targetAst.value.length);
       recorder.insertLeft(offset, newTarget);

packages/schematics/angular/migrations/update-10/update-module-and-target-compiler-options_spec.ts

@@ -131,11 +131,23 @@ describe('Migration to update target and module compiler options', () => {
     expect(target).toBe('es2018');
   });
 
-
   it(`should remove module in 'tsconfig.server.json'`, async () => {
     const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
-    const { module, target } = readJsonFile(newTree, 'src/tsconfig.server.json').compilerOptions;
+    const { module } = readJsonFile(newTree, 'src/tsconfig.server.json').compilerOptions;
     expect(module).toBeUndefined();
-    expect(target).toBeUndefined();
+  });
+
+  it(`should add target in 'tsconfig.server.json'`, async () => {
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    const { target } = readJsonFile(newTree, 'src/tsconfig.server.json').compilerOptions;
+    expect(target).toBe('es2016');
+  });
+
+  it(`should update target to es2016 in 'tsconfig.server.json'`, async () => {
+    tree.delete('src/tsconfig.server.json');
+    createJsonFile(tree, 'src/tsconfig.server.json', { compilerOptions: { module: 'commonjs', target: 'es5' } });
+    const newTree = await schematicRunner.runSchematicAsync(schematicName, {}, tree).toPromise();
+    const { target } = readJsonFile(newTree, 'src/tsconfig.server.json').compilerOptions;
+    expect(target).toBe('es2016');
   });
 });

packages/schematics/angular/universal/files/root/tsconfig.server.json.template

@@ -2,6 +2,7 @@
   "extends": "./<%= tsConfigExtends %>",
   "compilerOptions": {
     "outDir": "<%= relativePathToWorkspaceRoot %>/out-tsc/server",
+    "target": "es2016",
     "types": [
       "node"
     ]

packages/schematics/angular/universal/index_spec.ts

@@ -92,6 +92,7 @@ describe('Universal Schematic', () => {
       extends: './tsconfig.app.json',
       compilerOptions: {
         outDir: './out-tsc/server',
+        target: 'es2016',
         types: ['node'],
       },
       files: [
@@ -116,6 +117,7 @@ describe('Universal Schematic', () => {
       extends: './tsconfig.app.json',
       compilerOptions: {
         outDir: '../../out-tsc/server',
+        target: 'es2016',
         types: ['node'],
       },
       files: [