fix(perf): exclude entire /_next/static/ dir from generated function

src/build/templates/handler-monorepo.tmpl.js

@@ -53,4 +53,9 @@ export default async function (req, context) {
 export const config = {
   path: '/*',
   preferStatic: true,
+  excludedPath: [
+    // We use `preferStatic: true` so we already won't run this on *existing* static assets,
+    // but by excluding this entire path we also avoid invoking the function just to 404.
+    '/_next/static/*',
+  ],
 }

src/build/templates/handler.tmpl.js

@@ -46,4 +46,9 @@ export default async function handler(req, context) {
 export const config = {
   path: '/*',
   preferStatic: true,
+  excludedPath: [
+    // We use `preferStatic: true` so we already won't run this on *existing* static assets,
+    // but by excluding this entire path we also avoid invoking the function just to 404.
+    '/_next/static/*',
+  ],
 }

tests/e2e/simple-app.test.ts

@@ -1,6 +1,8 @@
 import { expect, type Locator } from '@playwright/test'
 import { nextVersionSatisfies } from '../utils/next-version-helpers.mjs'
 import { test } from '../utils/playwright-helpers.js'
+import { join } from 'node:path'
+import { readdir } from 'node:fs/promises'
 
 const expectImageWasLoaded = async (locator: Locator) => {
   expect(await locator.evaluate((img: HTMLImageElement) => img.naturalHeight)).toBeGreaterThan(0)
@@ -282,3 +284,27 @@ test('can require CJS module that is not bundled', async ({ simple }) => {
   expect(parsedBody.notBundledCJSModule.isBundled).toEqual(false)
   expect(parsedBody.bundledCJSModule.isBundled).toEqual(true)
 })
+
+test('serves a 200 for an existing static asset without invoking a function', async ({
+  page,
+  simple,
+}) => {
+  // Since assets are hashed, we can't hardcode anything here. Find something to fetch.
+  const [staticAsset] = await readdir(join(simple.isolatedFixtureRoot, '.next', 'static', 'chunks'))
+  expect(staticAsset).toBeDefined()
+
+  const response = await page.goto(`${simple.url}/_next/static/chunks/${staticAsset}`)
+
+  expect(response?.status()).toBe(200)
+  expect(response?.headers()).not.toHaveProperty('x-nf-function-type')
+})
+
+test('serves a 404 for a nonexistent static asset without invoking a function', async ({
+  page,
+  simple,
+}) => {
+  const response = await page.goto(`${simple.url}/_next/static/stale123abcdef.js`)
+
+  expect(response?.status()).toBe(404)
+  expect(response?.headers()).not.toHaveProperty('x-nf-function-type')
+})

tests/utils/create-e2e-fixture.ts

@@ -21,6 +21,7 @@ export interface DeployResult {
   deployID: string
   url: string
   logs: string
+  isolatedFixtureRoot: string
 }
 
 type PackageManager = 'npm' | 'pnpm' | 'yarn' | 'bun' | 'berry'
@@ -92,6 +93,7 @@ export const createE2EFixture = async (fixture: string, config: E2EConfig = {})
       cleanup: _cleanup,
       deployID: result.deployID,
       url: result.url,
+      isolatedFixtureRoot,
     }
   } catch (error) {
     await _cleanup(true)