rename __fetch_polyfill to installFetch (#4111)

* rename __fetch_polyfill to installFetch

* update adapters

* tidy up changesets

* fix types

Author: Rich-Harris

.changeset/slow-dots-know.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+[breaking] Rename `__fetch_polyfill` to `installFetch`, remove fetch exports

.changeset/tricky-bees-yell.md

@@ -0,0 +1,7 @@
+---
+'@sveltejs/adapter-netlify': patch
+'@sveltejs/adapter-node': patch
+'@sveltejs/adapter-vercel': patch
+---
+
+Rename `__fetch_polyfill` to `installFetch`

packages/adapter-netlify/src/shims.js

@@ -1,2 +1,2 @@
-import { __fetch_polyfill } from '@sveltejs/kit/install-fetch';
-__fetch_polyfill();
+import { installFetch } from '@sveltejs/kit/install-fetch';
+installFetch();

packages/adapter-node/src/shims.js

@@ -1,2 +1,2 @@
-import { __fetch_polyfill } from '@sveltejs/kit/install-fetch';
-__fetch_polyfill();
+import { installFetch } from '@sveltejs/kit/install-fetch';
+installFetch();

packages/adapter-vercel/files/shims.js

@@ -1,2 +1,2 @@
-import { __fetch_polyfill } from '@sveltejs/kit/install-fetch';
-__fetch_polyfill();
+import { installFetch } from '@sveltejs/kit/install-fetch';
+installFetch();

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

@@ -2,7 +2,7 @@ import { readFileSync, writeFileSync } from 'fs';
 import { dirname, join, resolve as resolve_path } from 'path';
 import { pathToFileURL, URL } from 'url';
 import { mkdirp } from '../../../utils/filesystem.js';
-import { __fetch_polyfill } from '../../../install-fetch.js';
+import { installFetch } from '../../../install-fetch.js';
 import { SVELTE_KIT } from '../../constants.js';
 import { is_root_relative, normalize_path, resolve } from '../../../utils/url.js';
 import { queue } from './queue.js';
@@ -63,7 +63,7 @@ export async function prerender({ cwd, out, log, config, build_data, fallback, a
 		return prerendered;
 	}
 
-	__fetch_polyfill();
+	installFetch();
 
 	const server_root = resolve_path(cwd, `${SVELTE_KIT}/output`);
 

packages/kit/src/core/dev/plugin.js

@@ -3,7 +3,7 @@ import path from 'path';
 import { URL } from 'url';
 import colors from 'kleur';
 import sirv from 'sirv';
-import { __fetch_polyfill } from '../../install-fetch.js';
+import { installFetch } from '../../install-fetch.js';
 import { create_app } from '../create_app/index.js';
 import create_manifest_data from '../create_manifest_data/index.js';
 import { getRequest, setResponse } from '../../node.js';
@@ -36,7 +36,7 @@ export async function create_plugin(config, cwd) {
 		name: 'vite-plugin-svelte-kit',
 
 		configureServer(vite) {
-			__fetch_polyfill();
+			installFetch();
 
 			/** @type {import('types').SSRManifest} */
 			let manifest;

packages/kit/src/core/preview/index.js

@@ -5,7 +5,7 @@ import { join, resolve } from 'path';
 import sirv from 'sirv';
 import { pathToFileURL } from 'url';
 import { getRequest, setResponse } from '../../node.js';
-import { __fetch_polyfill } from '../../install-fetch.js';
+import { installFetch } from '../../install-fetch.js';
 import { SVELTE_KIT, SVELTE_KIT_ASSETS } from '../constants.js';
 
 /** @param {string} dir */
@@ -31,7 +31,7 @@ export async function preview({
 	https: use_https = false,
 	cwd = process.cwd()
 }) {
-	__fetch_polyfill();
+	installFetch();
 
 	const index_file = resolve(cwd, `${SVELTE_KIT}/output/server/index.js`);
 	const manifest_file = resolve(cwd, `${SVELTE_KIT}/output/server/manifest.js`);

packages/kit/src/install-fetch.js

@@ -1,7 +1,7 @@
 import fetch, { Response, Request, Headers } from 'node-fetch';
 
 // exported for dev/preview and node environments
-export function __fetch_polyfill() {
+export function installFetch() {
 	Object.defineProperties(globalThis, {
 		fetch: {
 			enumerable: true,
@@ -25,6 +25,3 @@ export function __fetch_polyfill() {
 		}
 	});
 }
-
-// exported for esbuild shims in adapters
-export { fetch, Response, Request, Headers };

packages/kit/types/ambient.d.ts

@@ -281,11 +281,10 @@ declare module '@sveltejs/kit/hooks' {
  * A polyfill for `fetch` and its related interfaces, used by adapters for environments that don't provide a native implementation.
  */
 declare module '@sveltejs/kit/install-fetch' {
-	import fetch, { Headers, Request, Response } from 'node-fetch';
-
-	export function __fetch_polyfill(): void;
-
-	export { fetch, Headers, Request, Response };
+	/**
+	 * Make `fetch`, `Headers`, `Request` and `Response` available as globals, via `node-fetch`
+	 */
+	export function installFetch(): void;
 }
 
 /**