feat(adapters): Add back adapter.esbuild to allow configuration of bundling step

.changeset/yellow-clouds-kick.md

@@ -0,0 +1,7 @@
+---
+'@sveltejs/adapter-cloudflare': minor
+'@sveltejs/adapter-netlify': minor
+'@sveltejs/adapter-vercel': minor
+---
+
+feat: Add back esbuild argument to adapter configuration

packages/adapter-cloudflare/index.d.ts

@@ -1,8 +1,25 @@
 import { Adapter } from '@sveltejs/kit';
+import { BuildOptions } from 'esbuild';
 import './ambient.js';
 
 export default function plugin(options?: AdapterOptions): Adapter;
 
+interface DefaultEsbuildOptions {
+	platform: 'browser';
+	conditions: ['worker', 'browser'];
+	sourcemap: 'linked';
+	target: 'es2022';
+	entryPoints: [string];
+	outfile: string;
+	allowOverwrite: true;
+	format: 'esm';
+	bundle: true;
+}
+
+type esbuild = (
+	defaultOptions: DefaultEsbuildOptions
+) => Required<Pick<BuildOptions, keyof DefaultEsbuildOptions>> & Partial<BuildOptions>;
+
 export interface AdapterOptions {
 	/**
 	 * Customize the automatically-generated `_routes.json` file
@@ -30,6 +47,8 @@ export interface AdapterOptions {
 		 */
 		exclude?: string[];
 	};
+
+	esbuild?: esbuild;
 }
 
 export interface RoutesJSONSpec {

packages/adapter-cloudflare/index.js

@@ -45,7 +45,8 @@ export default function (options = {}) {
 				}
 			});
 
-			await esbuild.build({
+			/** @type { import('.').DefaultEsbuildOptions } */
+			const default_bundler_props = {
 				platform: 'browser',
 				conditions: ['worker', 'browser'],
 				sourcemap: 'linked',
@@ -55,7 +56,13 @@ export default function (options = {}) {
 				allowOverwrite: true,
 				format: 'esm',
 				bundle: true
-			});
+			};
+
+			const bundler_props = options['esbuild']
+				? options['esbuild'](default_bundler_props)
+				: default_bundler_props;
+
+			await esbuild.build(bundler_props);
 		}
 	};
 }

packages/adapter-netlify/index.d.ts

@@ -1,4 +1,23 @@
 import { Adapter } from '@sveltejs/kit';
+import { BuildOptions } from 'esbuild';
 import './ambient.js';
 
-export default function plugin(opts?: { split?: boolean; edge?: boolean }): Adapter;
+interface DefaultEsbuildOptions {
+	entryPoints: [string];
+	outfile: '.netlify/edge-functions/render.js';
+	bundle: true;
+	format: 'esm';
+	platform: 'browser';
+	sourcemap: 'linked';
+	target: 'es2020';
+}
+
+type esbuild = (
+	defaultOptions: DefaultEsbuildOptions
+) => Required<Pick<BuildOptions, keyof DefaultEsbuildOptions>> & Partial<BuildOptions>;
+
+export default function plugin(opts?: {
+	split?: boolean;
+	edge?: boolean;
+	esbuild?: esbuild;
+}): Adapter;

packages/adapter-netlify/index.js

@@ -1,7 +1,7 @@
 import { appendFileSync, existsSync, readdirSync, readFileSync, writeFileSync } from 'node:fs';
 import { dirname, join, resolve, posix } from 'node:path';
 import { fileURLToPath } from 'node:url';
-import esbuild from 'esbuild';
+import esbuild_bundler from 'esbuild';
 import toml from '@iarna/toml';
 
 /**
@@ -36,7 +36,7 @@ const edge_set_in_env_var =
 const FUNCTION_PREFIX = 'sveltekit-';
 
 /** @type {import('.').default} */
-export default function ({ split = false, edge = edge_set_in_env_var } = {}) {
+export default function ({ split = false, edge = edge_set_in_env_var, esbuild = null } = {}) {
 	return {
 		name: '@sveltejs/adapter-netlify',
 
@@ -88,7 +88,13 @@ export default function ({ split = false, edge = edge_set_in_env_var } = {}) {
 					throw new Error('Cannot use `split: true` alongside `edge: true`');
 				}
 
-				await generate_edge_functions({ builder });
+				if (esbuild && typeof esbuild !== 'function') {
+					throw new Error(
+						`Type of esbuild must be a function if defined. Type provided ${typeof esbuild}`
+					);
+				}
+
+				await generate_edge_functions({ builder, esbuild_props: esbuild });
 			} else {
 				await generate_lambda_functions({ builder, split, publish });
 			}
@@ -98,8 +104,9 @@ export default function ({ split = false, edge = edge_set_in_env_var } = {}) {
 /**
  * @param { object } params
  * @param {import('@sveltejs/kit').Builder} params.builder
+ * @param {import('.').esbuild} params.esbuild_props
  */
-async function generate_edge_functions({ builder }) {
+async function generate_edge_functions({ builder, esbuild_props }) {
 	const tmp = builder.getBuildDirectory('netlify-tmp');
 	builder.rimraf(tmp);
 	builder.mkdirp(tmp);
@@ -144,15 +151,22 @@ async function generate_edge_functions({ builder }) {
 		)});\n`
 	);
 
-	await esbuild.build({
+	/** @type { import('.').DefaultEsbuildOptions } */
+	const default_bundler_props = {
 		entryPoints: [`${tmp}/entry.js`],
 		outfile: '.netlify/edge-functions/render.js',
 		bundle: true,
 		format: 'esm',
 		platform: 'browser',
 		sourcemap: 'linked',
 		target: 'es2020'
-	});
+	};
+
+	const bundler_props = esbuild_props
+		? esbuild_props(default_bundler_props)
+		: default_bundler_props;
+
+	await esbuild_bundler.build(bundler_props);
 
 	writeFileSync('.netlify/edge-functions/manifest.json', JSON.stringify(edge_manifest));
 }

packages/adapter-vercel/index.d.ts

@@ -1,4 +1,5 @@
 import { Adapter } from '@sveltejs/kit';
+import { BuildOptions } from 'esbuild';
 import './ambient.js';
 
 export default function plugin(config?: Config): Adapter;
@@ -51,6 +52,22 @@ export interface ServerlessConfig {
 	};
 }
 
+interface DefaultEsbuildOptions {
+	entryPoints: [string];
+	outfile: string;
+	target: 'es2020';
+	bundle: true;
+	platform: 'browser';
+	format: 'esm';
+	external?: string[];
+	sourcemap: 'linked';
+	banner: { js: 'globalThis.global = globalThis;' };
+}
+
+type esbuild = (
+	defaultOptions: DefaultEsbuildOptions
+) => Required<Pick<BuildOptions, keyof DefaultEsbuildOptions>> & Partial<BuildOptions>;
+
 export interface EdgeConfig {
 	/**
 	 * Whether to use [Edge Functions](https://vercel.com/docs/concepts/functions/edge-functions) or [Serverless Functions](https://vercel.com/docs/concepts/functions/serverless-functions)
@@ -75,6 +92,12 @@ export interface EdgeConfig {
 	 * If `true`, this route will always be deployed as its own separate function
 	 */
 	split?: boolean;
+
+	/**
+	 * Advanced. Modify the bundling step's config
+	 * @see https://esbuild.github.io/api/#build
+	 */
+	esbuild?: esbuild;
 }
 
 export type Config = EdgeConfig | ServerlessConfig;

packages/adapter-vercel/index.js

@@ -114,7 +114,8 @@ const plugin = function (defaults = {}) {
 					`export const manifest = ${builder.generateManifest({ relativePath, routes })};\n`
 				);
 
-				await esbuild.build({
+				/** @type { import('.').DefaultEsbuildOptions } */
+				const default_bundler_props = {
 					entryPoints: [`${tmp}/edge.js`],
 					outfile: `${dirs.functions}/${name}.func/index.js`,
 					target: 'es2020', // TODO verify what the edge runtime supports
@@ -124,7 +125,22 @@ const plugin = function (defaults = {}) {
 					external: config.external,
 					sourcemap: 'linked',
 					banner: { js: 'globalThis.global = globalThis;' }
-				});
+				};
+
+				if (defaults['esbuild'] && typeof defaults['esbuild'] !== 'function') {
+					throw new Error(
+						`Type of esbuild must be a function if defined. Type provided ${typeof defaults[
+							'esbuild'
+						]}`
+					);
+				}
+
+				/** @type { import('.').DefaultEsbuildOptions } */
+				const bundler_props = defaults['esbuild']
+					? defaults['esbuild'](default_bundler_props)
+					: default_bundler_props;
+
+				await esbuild.build(bundler_props);
 
 				write(
 					`${dirs.functions}/${name}.func/.vc-config.json`,