breaking: require Node 18.13 or newer

.changeset/rotten-penguins-hope.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/adapter-node': major
+---
+
+breaking: remove polyfill option. fetch APIs will now always come from the platform being used. File and crypto APIs will be polyfilled if not available

.changeset/thick-suits-help.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': major
+---
+
+breaking: require Node 18.13 or newer

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
       - uses: pnpm/action-setup@v2.4.0
       - uses: actions/setup-node@v4
         with:
-          node-version: '16.x'
+          node-version: '18.x'
           cache: pnpm
       - run: pnpm install --frozen-lockfile
       - run: pnpm run lint
@@ -39,9 +39,6 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - node-version: 16
-            os: ubuntu-latest
-            e2e-browser: 'chromium'
           - node-version: 18
             os: ubuntu-latest
             e2e-browser: 'chromium'
@@ -79,27 +76,27 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - node-version: 16
+          - node-version: 18
             os: windows-2019 # slowness reported on newer versions https://github.com/actions/runner-images/issues/5166
             e2e-browser: 'chromium'
             mode: 'dev'
-          - node-version: 16
+          - node-version: 18
             os: ubuntu-latest
             e2e-browser: 'firefox'
             mode: 'dev'
-          - node-version: 16
+          - node-version: 18
             os: macOS-latest
             e2e-browser: 'webkit'
             mode: 'dev'
-          - node-version: 16
+          - node-version: 18
             os: windows-2019 # slowness reported on newer versions https://github.com/actions/runner-images/issues/5166
             e2e-browser: 'chromium'
             mode: 'build'
-          - node-version: 16
+          - node-version: 18
             os: ubuntu-latest
             e2e-browser: 'firefox'
             mode: 'build'
-          - node-version: 16
+          - node-version: 18
             os: macOS-latest
             e2e-browser: 'webkit'
             mode: 'build'
@@ -134,7 +131,7 @@ jobs:
       - uses: pnpm/action-setup@v2.4.0
       - uses: actions/setup-node@v4
         with:
-          node-version: 16
+          node-version: 18
           cache: pnpm
       - run: pnpm install --frozen-lockfile
       - run: cd packages/kit && pnpm prepublishOnly

documentation/docs/25-build-and-deploy/40-adapter-node.md

@@ -131,8 +131,7 @@ export default {
 			// default options are shown
 			out: 'build',
 			precompress: false,
-			envPrefix: '',
-			polyfill: true
+			envPrefix: ''
 		})
 	}
 };
@@ -161,12 +160,6 @@ MY_CUSTOM_ORIGIN=https://my.site \
 node build
 ```
 
-### polyfill
-
-Controls whether your build will load polyfills for missing modules. It defaults to `true`, and should only be disabled when using Node 18.11 or greater.
-
-Note: to use Node's built-in `crypto` global with Node 18 you will need to use the `--experimental-global-webcrypto` flag. This flag is not required with Node 20.
-
 ## Custom server
 
 The adapter creates two files in your build directory — `index.js` and `handler.js`. Running `index.js` — e.g. `node build`, if you use the default build directory — will start a server on the configured port.

packages/adapter-auto/package.json

@@ -32,7 +32,7 @@
 	"devDependencies": {
 		"@sveltejs/kit": "workspace:^",
 		"@sveltejs/vite-plugin-svelte": "^3.0.0",
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"typescript": "^5.3.2"
 	},
 	"dependencies": {

packages/adapter-cloudflare-workers/package.json

@@ -36,7 +36,7 @@
 	},
 	"devDependencies": {
 		"@cloudflare/kv-asset-handler": "^0.3.0",
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"typescript": "^5.3.2"
 	},
 	"peerDependencies": {

packages/adapter-cloudflare/package.json

@@ -37,7 +37,7 @@
 		"worktop": "0.8.0-next.15"
 	},
 	"devDependencies": {
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"@types/ws": "^8.5.3",
 		"typescript": "^5.3.2"
 	},

packages/adapter-netlify/package.json

@@ -44,7 +44,7 @@
 		"@rollup/plugin-node-resolve": "^15.2.3",
 		"@sveltejs/kit": "workspace:^",
 		"@sveltejs/vite-plugin-svelte": "^3.0.0",
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"@types/set-cookie-parser": "^2.4.2",
 		"rollup": "^4.2.0",
 		"typescript": "^5.3.2",

packages/adapter-node/index.d.ts

@@ -9,7 +9,6 @@ interface AdapterOptions {
 	out?: string;
 	precompress?: boolean;
 	envPrefix?: string;
-	polyfill?: boolean;
 }
 
 export default function plugin(options?: AdapterOptions): Adapter;

packages/adapter-node/index.js

@@ -9,7 +9,7 @@ const files = fileURLToPath(new URL('./files', import.meta.url).href);
 
 /** @type {import('./index.js').default} */
 export default function (opts = {}) {
-	const { out = 'build', precompress, envPrefix = '', polyfill = true } = opts;
+	const { out = 'build', precompress, envPrefix = '' } = opts;
 
 	return {
 		name: '@sveltejs/adapter-node',
@@ -86,11 +86,6 @@ export default function (opts = {}) {
 					ENV_PREFIX: JSON.stringify(envPrefix)
 				}
 			});
-
-			// If polyfills aren't wanted then clear the file
-			if (!polyfill) {
-				writeFileSync(`${out}/shims.js`, '', 'utf-8');
-			}
 		}
 	};
 }

packages/adapter-node/package.json

@@ -36,7 +36,7 @@
 		"@polka/url": "^1.0.0-next.23",
 		"@sveltejs/kit": "workspace:^",
 		"@sveltejs/vite-plugin-svelte": "^3.0.0",
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"c8": "^8.0.0",
 		"polka": "^1.0.0-next.23",
 		"sirv": "^2.0.3",

packages/adapter-static/package.json

@@ -33,7 +33,7 @@
 		"@playwright/test": "1.30.0",
 		"@sveltejs/kit": "workspace:^",
 		"@sveltejs/vite-plugin-svelte": "^3.0.0",
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"sirv": "^2.0.3",
 		"svelte": "^4.2.7",
 		"typescript": "^5.3.2",

packages/adapter-vercel/package.json

@@ -37,7 +37,7 @@
 	"devDependencies": {
 		"@sveltejs/kit": "workspace:^",
 		"@sveltejs/vite-plugin-svelte": "^3.0.0",
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"typescript": "^5.3.2",
 		"vitest": "^0.34.5"
 	},

packages/enhanced-img/package.json

@@ -32,7 +32,7 @@
 	},
 	"devDependencies": {
 		"@types/estree": "^1.0.2",
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"estree-walker": "^3.0.3",
 		"rollup": "^4.2.0",
 		"svelte": "^4.2.7",

packages/kit/package.json

@@ -21,14 +21,13 @@
 		"sade": "^1.8.1",
 		"set-cookie-parser": "^2.6.0",
 		"sirv": "^2.0.2",
-		"tiny-glob": "^0.2.9",
-		"undici": "~5.26.2"
+		"tiny-glob": "^0.2.9"
 	},
 	"devDependencies": {
 		"@playwright/test": "1.30.0",
 		"@sveltejs/vite-plugin-svelte": "^3.0.0",
 		"@types/connect": "^3.4.35",
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"@types/sade": "^1.7.4",
 		"@types/set-cookie-parser": "^2.4.2",
 		"dts-buddy": "^0.4.1",
@@ -96,6 +95,6 @@
 	},
 	"types": "types/index.d.ts",
 	"engines": {
-		"node": "^16.14 || >=18"
+		"node": ">=18.13"
 	}
 }

packages/kit/src/core/postbuild/analyse.js

@@ -10,7 +10,6 @@ import {
 } from '../../utils/exports.js';
 import { load_config } from '../config/index.js';
 import { forked } from '../../utils/fork.js';
-import { should_polyfill } from '../../utils/platform.js';
 import { installPolyfills } from '../../exports/node/polyfills.js';
 import { resolvePath } from '../../exports/index.js';
 import { ENDPOINT_METHODS } from '../../constants.js';
@@ -36,9 +35,7 @@ async function analyse({ manifest_path, env }) {
 	/** @type {import('types').ServerInternalModule} */
 	const internal = await import(pathToFileURL(`${server_root}/server/internal.js`).href);
 
-	if (should_polyfill) {
-		installPolyfills();
-	}
+	installPolyfills();
 
 	// configure `import { building } from '$app/environment'` —
 	// essential we do this before analysing the code

packages/kit/src/core/postbuild/prerender.js

@@ -3,7 +3,6 @@ import { dirname, join } from 'node:path';
 import { pathToFileURL } from 'node:url';
 import { installPolyfills } from '../../exports/node/polyfills.js';
 import { mkdirp, posixify, walk } from '../../utils/filesystem.js';
-import { should_polyfill } from '../../utils/platform.js';
 import { decode_uri, is_root_relative, resolve } from '../../utils/url.js';
 import { escape_html_attr } from '../../utils/escape.js';
 import { logger } from '../utils.js';
@@ -94,9 +93,7 @@ async function prerender({ out, manifest_path, metadata, verbose, env }) {
 	/** @type {import('types').Logger} */
 	const log = logger({ verbose });
 
-	if (should_polyfill) {
-		installPolyfills();
-	}
+	installPolyfills();
 
 	/** @type {Map<string, string>} */
 	const saved = new Map();

packages/kit/src/exports/node/polyfills.js

@@ -1,54 +1,25 @@
-import { ReadableStream, TransformStream, WritableStream } from 'node:stream/web';
 import buffer from 'node:buffer';
 import { webcrypto as crypto } from 'node:crypto';
-import { fetch, Response, Request, Headers, FormData, File as UndiciFile } from 'undici';
 
 // `buffer.File` was added in Node 18.13.0 while the `File` global was added in Node 20.0.0
-const File = /** @type {import('node:buffer') & { File?: File}} */ (buffer).File ?? UndiciFile;
+const File = /** @type {import('node:buffer') & { File?: File}} */ (buffer).File;
 
 /** @type {Record<string, any>} */
-const globals_post_node_18_11 = {
+const globals = {
 	crypto,
 	File
 };
 
-/** @type {Record<string, any>} */
-// TODO: remove this once we only support Node 18.11+ (the version multipart/form-data was added)
-const globals_pre_node_18_11 = {
-	crypto,
-	fetch,
-	Response,
-	Request,
-	Headers,
-	ReadableStream,
-	TransformStream,
-	WritableStream,
-	FormData,
-	File
-};
-
 // exported for dev/preview and node environments
 /**
  * Make various web APIs available as globals:
  * - `crypto`
- * - `fetch` (only in node < 18.11)
- * - `Headers` (only in node < 18.11)
- * - `Request` (only in node < 18.11)
- * - `Response` (only in node < 18.11)
+ * - `File`
  */
 export function installPolyfills() {
-	// Be defensive (we don't know in which environments this is called) and always apply if something goes wrong
-	let globals = globals_pre_node_18_11;
-	try {
-		const version = process.versions.node.split('.').map((n) => parseInt(n, 10));
-		if ((version[0] === 18 && version[1] >= 11) || version[0] > 18) {
-			globals = globals_post_node_18_11;
-		}
-	} catch (e) {
-		// ignore
-	}
-
 	for (const name in globals) {
+		if (name in globalThis) continue;
+
 		Object.defineProperty(globalThis, name, {
 			enumerable: true,
 			configurable: true,

packages/kit/src/exports/vite/dev/index.js

@@ -8,7 +8,6 @@ import { getRequest, setResponse } from '../../../exports/node/index.js';
 import { installPolyfills } from '../../../exports/node/polyfills.js';
 import { coalesce_to_error } from '../../../utils/error.js';
 import { posixify, resolve_entry, to_fs } from '../../../utils/filesystem.js';
-import { should_polyfill } from '../../../utils/platform.js';
 import { load_error_page } from '../../../core/config/index.js';
 import { SVELTE_KIT_ASSETS } from '../../../constants.js';
 import * as sync from '../../../core/sync/sync.js';
@@ -26,9 +25,7 @@ const cwd = process.cwd();
  * @return {Promise<Promise<() => void>>}
  */
 export async function dev(vite, vite_config, svelte_config) {
-	if (should_polyfill) {
-		installPolyfills();
-	}
+	installPolyfills();
 
 	const fetch = globalThis.fetch;
 	globalThis.fetch = (info, init) => {

packages/kit/src/exports/vite/preview/index.js

@@ -7,7 +7,6 @@ import { loadEnv, normalizePath } from 'vite';
 import { getRequest, setResponse } from '../../../exports/node/index.js';
 import { installPolyfills } from '../../../exports/node/polyfills.js';
 import { SVELTE_KIT_ASSETS } from '../../../constants.js';
-import { should_polyfill } from '../../../utils/platform.js';
 
 /** @typedef {import('http').IncomingMessage} Req */
 /** @typedef {import('http').ServerResponse} Res */
@@ -19,9 +18,7 @@ import { should_polyfill } from '../../../utils/platform.js';
  * @param {import('types').ValidatedConfig} svelte_config
  */
 export async function preview(vite, vite_config, svelte_config) {
-	if (should_polyfill) {
-		installPolyfills();
-	}
+	installPolyfills();
 
 	const { paths } = svelte_config.kit;
 	const assets = paths.assets ? SVELTE_KIT_ASSETS : paths.base;

packages/kit/src/runtime/server/page/csp.spec.js

@@ -2,8 +2,11 @@ import { webcrypto } from 'node:crypto';
 import { assert, beforeAll, test } from 'vitest';
 import { Csp } from './csp.js';
 
-// @ts-expect-error
-globalThis.crypto = webcrypto;
+// TODO: remove after bumping peer dependency to require Node 20
+if (!globalThis.crypto) {
+	// @ts-expect-error
+	globalThis.crypto = webcrypto;
+}
 
 beforeAll(() => {
 	// @ts-expect-error

packages/kit/test/apps/basics/test/server.test.js

@@ -1,6 +1,5 @@
 import { expect } from '@playwright/test';
 import { test } from '../../../utils.js';
-import { fetch } from 'undici';
 import { createHash, randomBytes } from 'node:crypto';
 
 /** @typedef {import('@playwright/test').Response} Response */

packages/migrate/package.json

@@ -33,7 +33,7 @@
 		"typescript": "^5.3.2"
 	},
 	"devDependencies": {
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"@types/prompts": "^2.4.1",
 		"@types/semver": "^7.5.0",
 		"prettier": "^3.1.0",

packages/package/package.json

@@ -18,7 +18,7 @@
 		"svelte2tsx": "~0.6.19"
 	},
 	"devDependencies": {
-		"@types/node": "^16.18.6",
+		"@types/node": "^18.19.1",
 		"@types/semver": "^7.5.0",
 		"svelte": "^4.2.7",
 		"svelte-preprocess": "^5.1.1",