feat(build): Add netlify-functions adapter

Why?
====

So we can build a bundle targetting the netlify-functions runtime.

How?
====

* Extend `EntryContentOptions` with `entryContentDefaultExportHook`
  to allow customizing the way the default export of the bundle is
  built.

* Alter `getEntryContent` to use the `entryContentDefaultExportHook`
  for defining the default export, defaulting to the previous
  behavior if not defined.

* Add `netlifyFunctionsBuildPlugin` as a new exported adapter that
  wraps the hono app in the `hono/netlify` `handle()` adapter and
  defines a `config` export to make the hono app respond to the
  root path in Netlify.

.changeset/tall-teachers-carry.md

@@ -0,0 +1,61 @@
+---
+'@hono/vite-build': minor
+---
+
+Added a new Netlify Functions build adapter.
+
+This adapter can be imported from `@hono/vite-build/netlify-functions` and will
+compile your Hono app to comply with the requirements of the Netlify Functions
+runtime.
+
+* The default export will have the `hono/netlify` adapter applied to it.
+* A `config` object will be exported, setting the function path to `'/*'` and
+  `preferStatic` to `true`.
+
+Please note, this is for the Netlify Functions runtime, not the Netlify Edge
+Functions runtime.
+
+Example:
+
+```ts
+// vite.config.ts
+import { defineConfig } from "vite";
+import devServer from "@hono/vite-dev-server";
+import build from "@hono/vite-build/netlify-functions";
+
+export default defineConfig({
+  plugins: [
+    devServer({
+      entry: "./src/index.ts",
+    }),
+    build({
+      entry: "./src/index.ts",
+      output: "functions/server/index.js"
+    })
+  ],
+});
+```
+
+If you also have a `public/publish` directory for your assets that should be
+published to the corresponding Netlify site, then after running a build, you
+would end up with a directory structure like:
+
+```
+dist/
+  functions/
+    server/
+      index.js
+  publish/
+    robots.txt
+    ....
+```
+
+then you can use a netlify.toml that looks like:
+
+```toml
+# https://ntl.fyi/file-based-build-config
+[build]
+command = "vite build"
+functions = "dist/functions"
+publish = "dist/publish"
+```

packages/build/README.md

@@ -9,6 +9,7 @@ Here are the modules included:
 - `@hono/vite-build/cloudflare-workers`
 - `@hono/vite-build/bun`
 - `@hono/vite-build/node`
+- `@hono/vite-build/netlify-functions`
 
 ## Usage
 
@@ -36,6 +37,7 @@ import build from '@hono/vite-build/bun'
 // import build from '@hono/vite-build/cloudflare-pages'
 // import build from '@hono/vite-build/cloudflare-workers'
 // import build from '@hono/vite-build/node'
+// import build from '@hono/vite-build/netlify-functions'
 
 export default defineConfig({
   plugins: [
@@ -51,7 +53,7 @@ export default defineConfig({
 
 ### Build
 
-Just run `vite build`.
+Just run `vite build`.
 
 ```bash
 npm exec vite build

packages/build/package.json

@@ -36,6 +36,10 @@
       "types": "./dist/adapter/cloudflare-workers/index.d.ts",
       "import": "./dist/adapter/cloudflare-workers/index.js"
     },
+    "./netlify-functions": {
+      "types": "./dist/adapter/netlify-functions/index.d.ts",
+      "import": "./dist/adapter/netlify-functions/index.js"
+    },
     "./deno": {
       "types": "./dist/adapter/deno/index.d.ts",
       "import": "./dist/adapter/deno/index.js"
@@ -57,6 +61,9 @@
       ],
       "cloudflare-workers": [
         "./dist/adapter/cloudflare-workers/index.d.ts"
+      ],
+      "netlify-functions": [
+        "./dist/adapter/netlify-functions/index.d.ts"
       ]
     }
   },

packages/build/src/adapter/netlify-functions/index.ts

@@ -0,0 +1,21 @@
+import type { Plugin } from 'vite'
+import type { BuildOptions } from '../../base.js'
+import buildPlugin from '../../base.js'
+
+export type NetlifyFunctionsBuildOptions = BuildOptions
+
+export default function netlifyFunctionsBuildPlugin(
+  pluginOptions?: NetlifyFunctionsBuildOptions
+): Plugin {
+  return {
+    ...buildPlugin({
+      ...{
+        entryContentBeforeHooks: [() => 'import { handle } from "hono/netlify"'],
+        entryContentAfterHooks: [() => 'export const config = { path: "/*", preferStatic: true }'],
+        entryContentDefaultExportHook: (appName) => `export default handle(${appName})`,
+      },
+      ...pluginOptions,
+    }),
+    name: '@hono/vite-build/netlify-functions',
+  }
+}

packages/build/src/base.ts

@@ -25,7 +25,10 @@ export type BuildOptions = {
 } & Omit<GetEntryContentOptions, 'entry'>
 
 export const defaultOptions: Required<
-  Omit<BuildOptions, 'entryContentAfterHooks' | 'entryContentBeforeHooks'>
+  Omit<
+    BuildOptions,
+    'entryContentAfterHooks' | 'entryContentBeforeHooks' | 'entryContentDefaultExportHook'
+  >
 > = {
   entry: ['src/index.ts', './src/index.tsx', './app/server.ts'],
   output: 'index.js',
@@ -46,7 +49,6 @@ const buildPlugin = (options: BuildOptions): Plugin => {
   const virtualEntryId = 'virtual:build-entry-module'
   const resolvedVirtualEntryId = '\0' + virtualEntryId
   let config: ResolvedConfig
-
   const output = options.output ?? defaultOptions.output
 
   return {
@@ -94,6 +96,7 @@ const buildPlugin = (options: BuildOptions): Plugin => {
           entry: Array.isArray(entry) ? entry : [entry],
           entryContentBeforeHooks: options.entryContentBeforeHooks,
           entryContentAfterHooks: options.entryContentAfterHooks,
+          entryContentDefaultExportHook: options.entryContentDefaultExportHook,
           staticPaths,
         })
       }

packages/build/src/entry/index.ts

@@ -13,6 +13,13 @@ export type GetEntryContentOptions = {
   entry: string[]
   entryContentBeforeHooks?: EntryContentHook[]
   entryContentAfterHooks?: EntryContentHook[]
+  /**
+   * Explicitly specify the default export for the app. Make sure your export
+   * incorporates the app passed as the `appName` argument.
+   *
+   * @default `export default ${appName}`
+   */
+  entryContentDefaultExportHook?: EntryContentHook
   staticPaths?: string[]
 }
 
@@ -67,7 +74,10 @@ export const getEntryContent = async (options: GetEntryContentOptions) => {
         throw new Error("Can't import modules from [${globStr}]")
       }`
 
-  const mainAppStr = `import { Hono } from 'hono'
+  const defaultExportHook =
+    options.entryContentDefaultExportHook ?? (() => 'export default mainApp')
+
+  return `import { Hono } from 'hono'
 const mainApp = new Hono()
 
 ${await hooksToString('mainApp', options.entryContentBeforeHooks)}
@@ -76,6 +86,5 @@ ${appStr}
 
 ${await hooksToString('mainApp', options.entryContentAfterHooks)}
 
-export default mainApp`
-  return mainAppStr
+${await hooksToString('mainApp', [defaultExportHook])}`
 }

packages/build/test/adapter.test.ts

@@ -3,6 +3,7 @@ import { existsSync, readFileSync, rmSync } from 'node:fs'
 import bunBuildPlugin from '../src/adapter/bun'
 import cloudflarePagesPlugin from '../src/adapter/cloudflare-pages'
 import denoBuildPlugin from '../src/adapter/deno'
+import netlifyFunctionsPlugin from '../src/adapter/netlify-functions'
 import nodeBuildPlugin from '../src/adapter/node'
 
 describe('Build Plugin with Bun Adapter', () => {
@@ -41,6 +42,43 @@ describe('Build Plugin with Bun Adapter', () => {
   })
 })
 
+describe('Build Plugin with Netlify Functions Adapter', () => {
+  const testDir = './test/mocks/app-static-files'
+  const entry = './src/server.ts'
+
+  afterEach(() => {
+    rmSync(`${testDir}/dist`, { recursive: true, force: true })
+  })
+
+  it('Should build the project correctly with the plugin', async () => {
+    const outputFile = `${testDir}/dist/index.js`
+
+    await build({
+      root: testDir,
+      plugins: [
+        netlifyFunctionsPlugin({
+          entry,
+          minify: false,
+        }),
+      ],
+    })
+
+    expect(existsSync(outputFile)).toBe(true)
+
+    const output = readFileSync(outputFile, 'utf-8')
+    expect(output).toContain('Hello World')
+    expect(output).toContain('{ path: "/*", preferStatic: true }')
+    expect(output).toContain('handle(mainApp)')
+
+    const outputFooTxt = readFileSync(`${testDir}/dist/foo.txt`, 'utf-8')
+    expect(outputFooTxt).toContain('foo')
+
+    const outputJsClientJs = readFileSync(`${testDir}/dist/js/client.js`, 'utf-8')
+    // eslint-disable-next-line quotes
+    expect(outputJsClientJs).toContain("console.log('foo')")
+  })
+})
+
 describe('Build Plugin with Cloudflare Pages Adapter', () => {
   const testDir = './test/mocks/app-static-files'
 

packages/dev-server/e2e-bun/mock/app.ts

@@ -9,7 +9,8 @@ app.get('/', (c) => {
 })
 
 app.get('/with-nonce', (c) => {
-  c.header('content-security-policy', 'script-src-elem \'self\' \'nonce-ZMuLoN/taD7JZTUXfl5yvQ==\';')
+  // eslint-disable-next-line quotes -- allowing using double-quotes bc of embedded single quotes
+  c.header('content-security-policy', "script-src-elem 'self' 'nonce-ZMuLoN/taD7JZTUXfl5yvQ==';")
   return c.html('<h1>Hello Vite!</h1>')
 })
 

packages/dev-server/e2e/mock/worker.ts

@@ -13,7 +13,8 @@ app.get('/', (c) => {
 })
 
 app.get('/with-nonce', (c) => {
-  c.header('content-security-policy', 'script-src-elem \'self\' \'nonce-ZMuLoN/taD7JZTUXfl5yvQ==\';')
+  // eslint-disable-next-line quotes -- allowing using double-quotes bc of embedded single quotes
+  c.header('content-security-policy', "script-src-elem 'self' 'nonce-ZMuLoN/taD7JZTUXfl5yvQ==';")
   return c.html('<h1>Hello Vite!</h1>')
 })
 

packages/ssg/test/app.ts

@@ -7,7 +7,7 @@ app.get('/', (c) => {
 })
 
 app.get('/dynamic-import', async (c) => {
-  // @ts-expect-error
+  // @ts-expect-error this is a test
   const module = await import('./sample.js')
   return c.text('Dynamic import works: ' + module.default)
 })