Allow marking externals in Pages Functions

.changeset/unlucky-kangaroos-brake.md

@@ -0,0 +1,7 @@
+---
+"wrangler": minor
+---
+
+feat: Allow marking external modules (with `--external`) to avoid bundling them when building Pages Functions
+
+It's useful for Pages Plugins which want to declare a peer dependency.

fixtures/pages-functions-app/package.json

@@ -19,5 +19,8 @@
 	},
 	"engines": {
 		"node": ">=16.13"
+	},
+	"dependencies": {
+		"is-odd": "^3.0.1"
 	}
 }

fixtures/pages-functions-app/tests/index.test.ts

@@ -124,6 +124,13 @@ describe("Pages Functions", () => {
 			expect(response.status).toBe(502);
 		});
 
+		it("should work with peer externals", async ({ expect }) => {
+			const response = await fetch(`http://${ip}:${port}/mounted-plugin/ext`);
+			const text = await response.text();
+			expect(text).toMatchInlineSnapshot(`"42 is even"`);
+			expect(response.status).toBe(200);
+		});
+
 		it("should mount a Plugin even if in a parameterized route", async ({
 			expect,
 		}) => {

fixtures/pages-plugin-example/functions/ext.ts

@@ -0,0 +1,5 @@
+import isOdd from "is-odd";
+
+export const onRequest: PagesFunction = () => {
+	return new Response(`42 is ${isOdd(42) ? "odd" : "even"}`);
+};

fixtures/pages-plugin-example/package.json

@@ -10,10 +10,11 @@
 		"public/"
 	],
 	"scripts": {
-		"build": "wrangler pages functions build --plugin --outdir=dist",
+		"build": "wrangler pages functions build --plugin --outdir=dist --external=is-odd",
 		"check:type": "tsc"
 	},
 	"devDependencies": {
+		"is-odd": "^3.0.1",
 		"wrangler": "workspace:*"
 	}
 }

fixtures/pages-plugin-mounted-on-root-app/package.json

@@ -19,5 +19,8 @@
 	},
 	"engines": {
 		"node": ">=16.13"
+	},
+	"dependencies": {
+		"is-odd": "^3.0.1"
 	}
 }

packages/wrangler/src/deployment-bundle/bundle.ts

@@ -85,6 +85,7 @@ export type BundleOptions = {
 	local: boolean;
 	projectRoot: string | undefined;
 	defineNavigatorUserAgent: boolean;
+	external?: string[];
 };
 
 /**
@@ -122,6 +123,7 @@ export async function bundleWorker(
 		local,
 		projectRoot,
 		defineNavigatorUserAgent,
+		external,
 	}: BundleOptions
 ): Promise<BundleResult> {
 	// We create a temporary directory for any one-off files we
@@ -284,7 +286,9 @@ export async function bundleWorker(
 			  }
 			: {}),
 		inject,
-		external: bundle ? ["__STATIC_CONTENT_MANIFEST"] : undefined,
+		external: bundle
+			? ["__STATIC_CONTENT_MANIFEST", ...(external ? external : [])]
+			: undefined,
 		format: entry.format === "modules" ? "esm" : "iife",
 		target: COMMON_ESBUILD_OPTIONS.target,
 		sourcemap: sourcemap ?? true,

packages/wrangler/src/pages/build.ts

@@ -123,6 +123,11 @@ export function Options(yargs: CommonYargsArgv) {
 				deprecated: true,
 				hidden: true,
 			},
+			external: {
+				describe: "A list of module imports to exclude from bundling",
+				type: "string",
+				array: true,
+			},
 		});
 }
 
@@ -146,6 +151,7 @@ export const Handler = async (args: PagesBuildArgs) => {
 			nodejsCompat,
 			legacyNodeCompat,
 			defineNavigatorUserAgent,
+			external,
 		} = validatedArgs;
 
 		try {
@@ -172,6 +178,7 @@ export const Handler = async (args: PagesBuildArgs) => {
 				routesOutputPath,
 				local: false,
 				defineNavigatorUserAgent,
+				external,
 			});
 		} catch (e) {
 			if (e instanceof FunctionsNoRoutesError) {
@@ -213,6 +220,7 @@ export const Handler = async (args: PagesBuildArgs) => {
 			legacyNodeCompat,
 			workerScriptPath,
 			defineNavigatorUserAgent,
+			external,
 		} = validatedArgs;
 
 		/**
@@ -243,6 +251,7 @@ export const Handler = async (args: PagesBuildArgs) => {
 					watch,
 					nodejsCompat,
 					defineNavigatorUserAgent,
+					externalModules: external,
 				});
 			}
 		} else {
@@ -268,6 +277,7 @@ export const Handler = async (args: PagesBuildArgs) => {
 					routesOutputPath,
 					local: false,
 					defineNavigatorUserAgent,
+					external,
 				});
 			} catch (e) {
 				if (e instanceof FunctionsNoRoutesError) {

packages/wrangler/src/pages/buildFunctions.ts

@@ -39,6 +39,7 @@ export async function buildFunctions({
 		`./functionsRoutes-${Math.random()}.mjs`
 	),
 	defineNavigatorUserAgent,
+	external,
 }: Partial<
 	Pick<
 		PagesBuildArgs,
@@ -51,6 +52,7 @@ export async function buildFunctions({
 		| "watch"
 		| "plugin"
 		| "buildOutputDirectory"
+		| "external"
 	>
 > & {
 	functionsDirectory: string;
@@ -120,6 +122,7 @@ export async function buildFunctions({
 			functionsDirectory: absoluteFunctionsDirectory,
 			local,
 			defineNavigatorUserAgent,
+			external,
 		});
 	} else {
 		bundle = await buildWorkerFromFunctions({
@@ -137,6 +140,7 @@ export async function buildFunctions({
 			legacyNodeCompat,
 			nodejsCompat,
 			defineNavigatorUserAgent,
+			external,
 		});
 	}
 

packages/wrangler/src/pages/functions/buildPlugin.ts

@@ -24,6 +24,7 @@ export function buildPluginFromFunctions({
 	functionsDirectory,
 	local,
 	defineNavigatorUserAgent,
+	external,
 }: Options) {
 	const entry: Entry = {
 		file: resolve(getBasePath(), "templates/pages-template-plugin.ts"),
@@ -51,6 +52,7 @@ export function buildPluginFromFunctions({
 		nodejsCompat: true,
 		define: {},
 		doBindings: [], // Pages functions don't support internal Durable Objects
+		external,
 		plugins: [
 			buildNotifierPlugin(onEnd),
 			{

packages/wrangler/src/pages/functions/buildWorker.ts

@@ -32,6 +32,7 @@ export type Options = {
 	functionsDirectory: string;
 	local: boolean;
 	defineNavigatorUserAgent: boolean;
+	external?: string[];
 };
 
 export function buildWorkerFromFunctions({
@@ -49,6 +50,7 @@ export function buildWorkerFromFunctions({
 	functionsDirectory,
 	local,
 	defineNavigatorUserAgent,
+	external,
 }: Options) {
 	const entry: Entry = {
 		file: resolve(getBasePath(), "templates/pages-template-worker.ts"),
@@ -76,6 +78,7 @@ export function buildWorkerFromFunctions({
 			__FALLBACK_SERVICE__: JSON.stringify(fallbackService),
 		},
 		doBindings: [], // Pages functions don't support internal Durable Objects
+		external,
 		plugins: [
 			buildNotifierPlugin(onEnd),
 			{
@@ -170,7 +173,7 @@ export type RawOptions = {
 	outdir?: string;
 	directory: string;
 	bundle?: boolean;
-	external?: string[];
+	externalModules?: string[];
 	minify?: boolean;
 	sourcemap?: boolean;
 	watch?: boolean;
@@ -182,6 +185,7 @@ export type RawOptions = {
 	local: boolean;
 	additionalModules?: CfModule[];
 	defineNavigatorUserAgent: boolean;
+	external?: string[];
 };
 
 /**
@@ -197,7 +201,7 @@ export function buildRawWorker({
 	outdir,
 	directory,
 	bundle = true,
-	external,
+	externalModules,
 	minify = false,
 	sourcemap = false,
 	watch = false,
@@ -208,14 +212,15 @@ export function buildRawWorker({
 	local,
 	additionalModules = [],
 	defineNavigatorUserAgent,
+	external,
 }: RawOptions) {
 	const entry: Entry = {
 		file: workerScriptPath,
 		directory: resolve(directory),
 		format: "modules",
 		moduleRoot: resolve(directory),
 	};
-	const moduleCollector = external
+	const moduleCollector = externalModules
 		? noopModuleCollector
 		: createModuleCollector({ entry, findAdditionalModules: false });
 
@@ -230,18 +235,23 @@ export function buildRawWorker({
 		nodejsCompat,
 		define: {},
 		doBindings: [], // Pages functions don't support internal Durable Objects
+		external,
 		plugins: [
 			...plugins,
 			buildNotifierPlugin(onEnd),
-			...(external
+			...(externalModules
 				? [
 						// In some cases, we want to enable bundling in esbuild so that we can flatten a shim around the entrypoint, but we still don't want to actually bundle in all the chunks that a Worker references.
 						// This plugin allows us to mark those chunks as external so they are not inlined.
 						{
 							name: "external-fixer",
 							setup(pluginBuild) {
 								pluginBuild.onResolve({ filter: /.*/ }, async (args) => {
-									if (external.includes(resolve(args.resolveDir, args.path))) {
+									if (
+										externalModules.includes(
+											resolve(args.resolveDir, args.path)
+										)
+									) {
 										return { path: args.path, external: true };
 									}
 								});
@@ -296,7 +306,9 @@ export async function traverseAndBuildWorkerJSDirectory({
 	const bundleResult = await buildRawWorker({
 		workerScriptPath: entrypoint,
 		bundle: true,
-		external: additionalModules.map((m) => join(workerJSDirectory, m.name)),
+		externalModules: additionalModules.map((m) =>
+			join(workerJSDirectory, m.name)
+		),
 		outfile,
 		directory: buildOutputDirectory,
 		local: false,