[Wrangler] Build target ES2022 (#2720)

* upgrade the target for JavaScript to ES2022 which is supported in the Worker runtime

* Include the ES2022 change to entry ESBuild config & included ES2022 to the publish testing

* changed the test to handle ES2022 with top level await which will not build in ESBuild before ES2022

.changeset/perfect-knives-lie.md

@@ -0,0 +1,10 @@
+---
+"wrangler": patch
+---
+
+Fix: Upgraded to ES2022 for improved compatibility
+Upgraded worker code target version from ES2020 to ES2022 for better compatibility and unblocking of a workaround related to [issue #2029](https://github.com/cloudflare/workers-sdk/issues/2029). The worker runtime now uses the same V8 version as recent Chrome and is 99% ES2016+ compliant. The only thing we don't support on the Workers runtime, the remaining 1%, is the ES2022 RegEx feature as seen in the compat table for the latest Chrome version.
+
+Compatibility table: https://kangax.github.io/compat-table/es2016plus/
+
+[resolves #2716](https://github.com/cloudflare/workers-sdk/issues/2716)

packages/wrangler/src/__tests__/publish.test.ts

@@ -6489,9 +6489,22 @@ addEventListener('fetch', event => {});`
 		`);
 		});
 
-		it("should output to target es2020 even if tsconfig says otherwise", async () => {
+		it.only("should output to target es2022 even if tsconfig says otherwise", async () => {
 			writeWranglerToml();
 			writeWorkerSource();
+			fs.writeFileSync(
+				"./index.js",
+				`
+			import { foo } from "./another";
+			const topLevelAwait = await new Promise((resolve) => setTimeout(resolve, 0));
+
+			export default {
+  			async fetch(request) {
+
+    			return new Response("Hello world!");
+  			},
+			};`
+			);
 			fs.writeFileSync(
 				"tsconfig.json",
 				JSON.stringify({
@@ -6502,8 +6515,14 @@ addEventListener('fetch', event => {});`
 				})
 			);
 			mockSubDomainRequest();
+			/**
+			 * When we compile with es2022, we should preserve the export statement and top level await
+			 * If you attempt to target es2020 top level await will cause a build error
+			 * @error Build failed with 1 error:
+			 * index.js:3:25: ERROR: Top-level await is not available in the configured target environment ("es2020")
+			 */
 			mockUploadWorkerRequest({
-				expectedEntry: "export {", // just check that the export is preserved
+				expectedEntry: "export {", // check that the export is preserved
 			});
 			await runWrangler("publish index.js"); // this would throw if we tried to compile with es5
 			expect(std).toMatchInlineSnapshot(`
@@ -7448,7 +7467,7 @@ function mockLastDeploymentRequest() {
 function mockUploadWorkerRequest(
 	options: {
 		available_on_subdomain?: boolean;
-		expectedEntry?: string;
+		expectedEntry?: string | RegExp;
 		expectedMainModule?: string;
 		expectedType?: "esm" | "sw";
 		expectedBindings?: unknown;

packages/wrangler/src/bundle.ts

@@ -333,7 +333,8 @@ export async function bundleWorker(
 		inject,
 		external: ["__STATIC_CONTENT_MANIFEST"],
 		format: entry.format === "modules" ? "esm" : "iife",
-		target: "es2020",
+		// Our workerd runtime uses the same V8 version as recent Chrome, which is highly ES2022 compliant: https://kangax.github.io/compat-table/es2016plus/
+		target: "es2022",
 		sourcemap: sourcemap ?? true, // this needs to use ?? to accept false
 		// Include a reference to the output folder in the sourcemap.
 		// This is omitted by default, but we need it to properly resolve source paths in error output.

packages/wrangler/src/entry.ts

@@ -152,7 +152,7 @@ export default async function guessWorkerFormat(
 		metafile: true,
 		bundle: false,
 		format: "esm",
-		target: "es2020",
+		target: "es2022",
 		write: false,
 		loader: {
 			".js": "jsx",