Re-bundle server app in adapter-node (#1648)

* prepare adapter-node runtime for bundling

* add esbuild as dependency of adapter-node

* bundle app as part of adapter-node's adapt phase

* add changeset

* add require() shim for requires not transformed by esbuild

esbuild doesn't seem to transform require()s of Node builtins into
imports, so define a global.require for them.

Author: Conduitry

.changeset/tiny-socks-sparkle.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/adapter-node': patch
+---
+
+Bundle server-side app during adapt phase

packages/adapter-node/index.js

@@ -1,6 +1,7 @@
-import { copyFileSync } from 'fs';
+import { readFileSync } from 'fs';
 import { join } from 'path';
 import { fileURLToPath } from 'url';
+import esbuild from 'esbuild';
 
 /**
  * @param {{
@@ -18,11 +19,17 @@ export default function ({ out = 'build' } = {}) {
 			utils.copy_client_files(static_directory);
 			utils.copy_static_files(static_directory);
 
-			utils.log.minor('Copying server');
-			utils.copy_server_files(out);
-
+			utils.log.minor('Building server');
 			const files = fileURLToPath(new URL('./files', import.meta.url));
-			copyFileSync(`${files}/server.js`, `${out}/index.js`);
+			utils.copy(files, '.svelte-kit/node');
+			await esbuild.build({
+				entryPoints: ['.svelte-kit/node/index.js'],
+				outfile: join(out, 'index.js'),
+				bundle: true,
+				external: Object.keys(JSON.parse(readFileSync('package.json', 'utf8')).dependencies || {}),
+				format: 'esm',
+				platform: 'node'
+			});
 
 			utils.log.minor('Prerendering static pages');
 			await utils.prerender({

packages/adapter-node/package.json

@@ -20,6 +20,9 @@
 		"check-format": "prettier --check . --config ../../.prettierrc --ignore-path .gitignore",
 		"prepublishOnly": "npm run build"
 	},
+	"dependencies": {
+		"esbuild": "^0.12.5"
+	},
 	"devDependencies": {
 		"@rollup/plugin-json": "^4.1.0",
 		"@sveltejs/kit": "workspace:*",

packages/adapter-node/rollup.config.js

@@ -5,10 +5,10 @@ import json from '@rollup/plugin-json';
 export default {
 	input: 'src/index.js',
 	output: {
-		file: 'files/server.js',
+		file: 'files/index.js',
 		format: 'esm',
 		sourcemap: true
 	},
 	plugins: [nodeResolve(), commonjs(), json()],
-	external: ['./app.js', ...require('module').builtinModules]
+	external: ['../output/server/app.js', ...require('module').builtinModules]
 };

packages/adapter-node/src/index.js

@@ -1,10 +1,11 @@
+import './require_shim';
 import { createServer } from './server';
-/*eslint import/no-unresolved: [2, { ignore: ['\.\/app\.js$'] }]*/
-import * as app from './app.js';
+// TODO hardcoding the relative location makes this brittle
+import { render } from '../output/server/app.js'; // eslint-disable-line import/no-unresolved
 
 const { HOST = '0.0.0.0', PORT = 3000 } = process.env;
 
-const instance = createServer({ render: app.render }).listen(PORT, HOST, () => {
+const instance = createServer({ render }).listen(PORT, HOST, () => {
 	console.log(`Listening on port ${PORT}`);
 });
 

packages/adapter-node/src/require_shim.js

@@ -0,0 +1,2 @@
+import { createRequire } from 'module';
+global.require = createRequire(import.meta.url);