From f3d671138f17b6c8e56a7244f12c1cb896ed6904 Mon Sep 17 00:00:00 2001
From: Samuel Macleod <smacleod@cloudflare.com>
Date: Tue, 23 Jul 2024 16:33:21 +0100
Subject: [PATCH] Add header + caching to runtime type generation

---
 packages/wrangler/e2e/types.test.ts           | 38 ++++++++++++++++++-
 .../wrangler/src/type-generation/index.ts     |  3 +-
 .../src/type-generation/runtime/index.ts      | 20 +++++++++-
 packages/wrangler/src/workerd.d.ts            |  6 +++
 4 files changed, 61 insertions(+), 6 deletions(-)
 create mode 100644 packages/wrangler/src/workerd.d.ts

diff --git a/packages/wrangler/e2e/types.test.ts b/packages/wrangler/e2e/types.test.ts
index 9437312f229b..2fb3a8a678fc 100644
--- a/packages/wrangler/e2e/types.test.ts
+++ b/packages/wrangler/e2e/types.test.ts
@@ -1,5 +1,5 @@
 import { existsSync } from "node:fs";
-import { readFile } from "node:fs/promises";
+import { readFile, writeFile } from "node:fs/promises";
 import path from "node:path";
 import { describe, expect, it } from "vitest";
 import { dedent } from "../src/utils/dedent";
@@ -10,7 +10,7 @@ const seed = {
 		name = "test-worker"
 		main = "src/index.ts"
 		compatibility_date = "2023-01-01"
-		compatibility_flags = ["nodejs_compat"]
+		compatibility_flags = ["nodejs_compat", "no_global_navigator"]
 	`,
 	"src/index.ts": dedent`
 		export default {
@@ -130,4 +130,38 @@ describe("types", () => {
 			`📣 It looks like you have some Node.js compatibility turned on in your project. You might want to consider adding Node.js typings with "npm i --save-dev @types/node@20.8.3". Please see the docs for more details: https://developers.cloudflare.com/workers/languages/typescript/#transitive-loading-of-typesnode-overrides-cloudflareworkers-types`
 		);
 	});
+	it("should include header with version information in the generated types", async () => {
+		const helper = new WranglerE2ETestHelper();
+		await helper.seed(seed);
+		await helper.run(`wrangler types --x-include-runtime="./types.d.ts"`);
+
+		const file = (
+			await readFile(path.join(helper.tmpPath, "./types.d.ts"))
+		).toString();
+
+		expect(file.split("\n")[0]).match(
+			/\/\/ Runtime types generated with workerd@1\.\d+\.\d \d\d\d\d-\d\d-\d\d ([a-z_]+,?)*/
+		);
+	});
+	it("should not regenerate types if the header matches", async () => {
+		const helper = new WranglerE2ETestHelper();
+		await helper.seed(seed);
+		await helper.run(`wrangler types --x-include-runtime`);
+
+		const runtimeTypesFile = path.join(
+			helper.tmpPath,
+			"./.wrangler/types/runtime.d.ts"
+		);
+		const file = (await readFile(runtimeTypesFile)).toString();
+
+		const header = file.split("\n")[0];
+
+		await writeFile(runtimeTypesFile, header + "\n" + "SOME_RANDOM_DATA");
+
+		await helper.run(`wrangler types --x-include-runtime`);
+
+		const file2 = (await readFile(runtimeTypesFile)).toString();
+
+		expect(file2.split("\n")[1]).toBe("SOME_RANDOM_DATA");
+	});
 });
diff --git a/packages/wrangler/src/type-generation/index.ts b/packages/wrangler/src/type-generation/index.ts
index 4368459530ba..e598af83428f 100644
--- a/packages/wrangler/src/type-generation/index.ts
+++ b/packages/wrangler/src/type-generation/index.ts
@@ -489,8 +489,7 @@ function writeDTSFile({
 		fs.writeFileSync(
 			path,
 			[
-				`// Generated by Wrangler on ${new Date()}`,
-				`// by running \`${wranglerCommandUsed}\``,
+				`// Generated by Wrangler by running \`${wranglerCommandUsed}\``,
 				"",
 				combinedTypeStrings,
 			].join("\n")
diff --git a/packages/wrangler/src/type-generation/runtime/index.ts b/packages/wrangler/src/type-generation/runtime/index.ts
index 8e4ecffa35fa..4d38ba55a35d 100644
--- a/packages/wrangler/src/type-generation/runtime/index.ts
+++ b/packages/wrangler/src/type-generation/runtime/index.ts
@@ -1,6 +1,8 @@
 import { readFileSync } from "fs";
-import { writeFile } from "fs/promises";
+import { readFile, writeFile } from "fs/promises";
 import { Miniflare } from "miniflare";
+import { version } from "workerd";
+import { logger } from "../../logger";
 import { ensureDirectoryExists } from "../../utils/filesystem";
 import type { Config } from "../../config/config";
 
@@ -47,12 +49,26 @@ export async function generateRuntimeTypes({
 
 	await ensureDirectoryExists(outFile);
 
+	const header = `// Runtime types generated with workerd@${version} ${compatibility_date} ${compatibility_flags.join(",")}`;
+
+	try {
+		const existingTypes = await readFile(outFile, "utf8");
+		if (existingTypes.split("\n")[0] === header) {
+			logger.debug("Using cached runtime types: ", header);
+			return { outFile };
+		}
+	} catch (e) {
+		if ((e as { code: string }).code !== "ENOENT") {
+			throw e;
+		}
+	}
+
 	const types = await generate({
 		compatibilityDate: compatibility_date,
 		compatibilityFlags: compatibility_flags,
 	});
 
-	await writeFile(outFile, types, "utf8");
+	await writeFile(outFile, header + "\n" + types, "utf8");
 
 	return {
 		outFile,
diff --git a/packages/wrangler/src/workerd.d.ts b/packages/wrangler/src/workerd.d.ts
new file mode 100644
index 000000000000..1b6e6e04e334
--- /dev/null
+++ b/packages/wrangler/src/workerd.d.ts
@@ -0,0 +1,6 @@
+declare module "workerd" {
+	const path: string;
+	export default path;
+	export const compatibilityDate: string;
+	export const version: string;
+}