feat(adapters): expose esbuild configuration

.changeset/dull-numbers-hunt.md

@@ -0,0 +1,8 @@
+---
+'@sveltejs/adapter-cloudflare-workers': patch
+'@sveltejs/adapter-netlify': patch
+'@sveltejs/adapter-node': patch
+'@sveltejs/adapter-vercel': patch
+---
+
+feat(adapters): expose esbuild configuration

packages/adapter-cloudflare-workers/README.md

@@ -4,7 +4,7 @@ SvelteKit adapter that creates a Cloudflare Workers site using a function for dy
 
 This is very experimental; the adapter API isn't at all fleshed out, and things will definitely change.
 
-## Configuration
+## Basic Configuration
 
 This adapter expects to find a [wrangler.toml](https://developers.cloudflare.com/workers/platform/sites/configuration) file in the project root. It will determine where to write static assets and the worker based on the `site.bucket` and `site.entry-point` settings.
 
@@ -26,6 +26,37 @@ It's recommended that you add the `build` and `workers-site` folders (or whichev
 
 More info on configuring a cloudflare worker site can be found [here](https://developers.cloudflare.com/workers/platform/sites/start-from-existing)
 
+## Advanced Configuration
+
+### esbuild
+
+As an escape hatch, you may optionally specify a function which will receive the final esbuild options generated by this adapter and returns a modified esbuild configuration. The result of this function will be passed as-is to esbuild. The function can be async.
+
+For example, you may wish to add a plugin:
+
+```js
+adapterCfw({
+	esbuild(defaultOptions) {
+		return {
+			...defaultOptions,
+			plugins: []
+		};
+	}
+});
+```
+
+The default options for this version are as follows:
+
+```js
+{
+    entryPoints: ['.svelte-kit/cloudflare-workers/entry.js'],
+    outfile: `${entrypoint}/index.js`,
+    bundle: true,
+    target: 'es2020',
+    platform: 'browser'
+}
+```
+
 ## Changelog
 
 [The Changelog for this package is available on GitHub](https://github.com/sveltejs/kit/blob/master/packages/adapter-cloudflare-workers/CHANGELOG.md).

packages/adapter-cloudflare-workers/index.js

@@ -4,7 +4,16 @@ import esbuild from 'esbuild';
 import toml from '@iarna/toml';
 import { fileURLToPath } from 'url';
 
-export default function () {
+/**
+ * @typedef {import('esbuild').BuildOptions} BuildOptions
+ */
+
+/**
+ * @param {{
+ *   esbuild?: (defaultOptions: BuildOptions) => Promise<BuildOptions> | BuildOptions;
+ * }} options
+ **/
+export default function (options = { esbuild: (opts) => opts }) {
 	/** @type {import('@sveltejs/kit').Adapter} */
 	const adapter = {
 		name: '@sveltejs/adapter-cloudflare-workers',
@@ -29,14 +38,16 @@ export default function () {
 			utils.log.minor('Generating worker...');
 			utils.copy(`${files}/entry.js`, '.svelte-kit/cloudflare-workers/entry.js');
 
-			await esbuild.build({
+			const buildOptions = await options.esbuild({
 				entryPoints: ['.svelte-kit/cloudflare-workers/entry.js'],
 				outfile: `${entrypoint}/index.js`,
 				bundle: true,
 				target: 'es2020',
-				platform: 'node' // TODO would be great if we could generate ESM and use type = "javascript"
+				platform: 'browser' // TODO would be great if we could generate ESM and use type = "javascript"
 			});
 
+			await esbuild.build(buildOptions);
+
 			fs.writeFileSync(`${entrypoint}/package.json`, JSON.stringify({ main: 'index.js' }));
 
 			utils.log.info('Prerendering static pages...');

packages/adapter-netlify/README.md

@@ -53,6 +53,37 @@ During compilation a required "catch all" redirect rule is automatically appende
 2. Netlify's build bot parses your HTML files at deploy time, which means your form must be [prerendered](https://kit.svelte.dev/docs#ssr-and-javascript-prerender) as HTML. You can either add `export const prerender = true` to your `contact.svelte` to prerender just that page or set the `kit.prerender.force: true` option to prerender all pages.
 3. If your Netlify form has a [custom success message](https://docs.netlify.com/forms/setup/#success-messages) like `<form netlify ... action="/success">` then ensure the corresponding `/routes/success.svelte` exists and is prerendered.
 
+## Advanced Configuration
+
+### esbuild
+
+As an escape hatch, you may optionally specify a function which will receive the final esbuild options generated by this adapter and returns a modified esbuild configuration. The result of this function will be passed as-is to esbuild. The function can be async.
+
+For example, you may wish to add a plugin:
+
+```js
+adapterNetlify({
+	esbuild(defaultOptions) {
+		return {
+			...defaultOptions,
+			plugins: []
+		};
+	}
+});
+```
+
+The default options for this version are as follows:
+
+```js
+{
+	entryPoints: ['.svelte-kit/netlify/entry.js'],
+	outfile: `pathToFunctionsFolder/render/index.js`,
+	bundle: true,
+	inject: ['pathTo/shims.js'],
+	platform: 'node'
+}
+```
+
 ## Changelog
 
 [The Changelog for this package is available on GitHub](https://github.com/sveltejs/kit/blob/master/packages/adapter-netlify/CHANGELOG.md).

packages/adapter-netlify/index.js

@@ -4,7 +4,16 @@ import { fileURLToPath } from 'url';
 import esbuild from 'esbuild';
 import toml from '@iarna/toml';
 
-export default function () {
+/**
+ * @typedef {import('esbuild').BuildOptions} BuildOptions
+ */
+
+/**
+ * @param {{
+ *   esbuild?: (defaultOptions: BuildOptions) => Promise<BuildOptions> | BuildOptions;
+ * }} options
+ **/
+export default function (options = { esbuild: (opts) => opts }) {
 	/** @type {import('@sveltejs/kit').Adapter} */
 	const adapter = {
 		name: '@sveltejs/adapter-netlify',
@@ -20,14 +29,16 @@ export default function () {
 			utils.log.minor('Generating serverless function...');
 			utils.copy(join(files, 'entry.js'), '.svelte-kit/netlify/entry.js');
 
-			await esbuild.build({
+			const buildOptions = await options.esbuild({
 				entryPoints: ['.svelte-kit/netlify/entry.js'],
 				outfile: join(functions, 'render/index.js'),
 				bundle: true,
 				inject: [join(files, 'shims.js')],
 				platform: 'node'
 			});
 
+			await esbuild.build(buildOptions);
+
 			writeFileSync(join(functions, 'package.json'), JSON.stringify({ type: 'commonjs' }));
 
 			utils.log.info('Prerendering static pages...');

packages/adapter-node/README.md

@@ -45,6 +45,43 @@ HOST=127.0.0.1 PORT=4000 node build
 
 You can specify different environment variables if necessary using the `env` option.
 
+## Advanced Configuration
+
+### esbuild
+
+As an escape hatch, you may optionally specify a function which will receive the final esbuild options generated by this adapter and returns a modified esbuild configuration. The result of this function will be passed as-is to esbuild. The function can be async.
+
+For example, you may wish to add a plugin:
+
+```js
+adapterNode({
+	esbuild(defaultOptions) {
+		return {
+			...defaultOptions,
+			plugins: []
+		};
+	}
+});
+```
+
+The default options for this version are as follows:
+
+```js
+{
+	entryPoints: ['.svelte-kit/node/index.js'],
+	outfile: 'pathTo/index.js',
+	bundle: true,
+	external: allProductionDependencies, // from package.json
+	format: 'esm',
+	platform: 'node',
+	target: 'node12',
+	inject: ['pathTo/shims.js'],
+	define: {
+		esbuild_app_dir: `"${config.kit.appDir}"`
+	}
+}
+```
+
 ## Changelog
 
 [The Changelog for this package is available on GitHub](https://github.com/sveltejs/kit/blob/master/packages/adapter-node/CHANGELOG.md).

packages/adapter-node/index.js

@@ -16,6 +16,10 @@ import zlib from 'zlib';
 
 const pipe = promisify(pipeline);
 
+/**
+ * @typedef {import('esbuild').BuildOptions} BuildOptions
+ */
+
 /**
  * @param {{
  *   out?: string;
@@ -24,13 +28,17 @@ const pipe = promisify(pipeline);
  *     host?: string;
  *     port?: string;
  *   };
+ *   esbuild?: (defaultOptions: BuildOptions) => Promise<BuildOptions> | BuildOptions;
  * }} options
  */
-export default function ({
-	out = 'build',
-	precompress,
-	env: { host: host_env = 'HOST', port: port_env = 'PORT' } = {}
-} = {}) {
+export default function (
+	{
+		out = 'build',
+		precompress,
+		env: { host: host_env = 'HOST', port: port_env = 'PORT' } = {},
+		esbuild: esbuildConfig
+	} = { esbuild: (opts) => opts }
+) {
 	/** @type {import('@sveltejs/kit').Adapter} */
 	const adapter = {
 		name: '@sveltejs/adapter-node',
@@ -55,7 +63,7 @@ export default function ({
 					host_env
 				)}] || '0.0.0.0';\nexport const port = process.env[${JSON.stringify(port_env)}] || 3000;`
 			);
-			await esbuild.build({
+			const buildOptions = await esbuildConfig({
 				entryPoints: ['.svelte-kit/node/index.js'],
 				outfile: join(out, 'index.js'),
 				bundle: true,
@@ -68,6 +76,7 @@ export default function ({
 					esbuild_app_dir: '"' + config.kit.appDir + '"'
 				}
 			});
+			await esbuild.build(buildOptions);
 
 			utils.log.minor('Prerendering static pages');
 			await utils.prerender({

packages/adapter-vercel/README.md

@@ -19,6 +19,37 @@ export default {
 };
 ```
 
+## Advanced Configuration
+
+### esbuild
+
+As an escape hatch, you may optionally specify a function which will receive the final esbuild options generated by this adapter and returns a modified esbuild configuration. The result of this function will be passed as-is to esbuild. The function can be async.
+
+For example, you may wish to add a plugin:
+
+```js
+adapterVercel({
+	esbuild(defaultOptions) {
+		return {
+			...defaultOptions,
+			plugins: []
+		};
+	}
+});
+```
+
+The default options for this version are as follows:
+
+```js
+{
+	entryPoints: ['.svelte-kit/vercel/entry.js'],
+	outfile: `pathToLambdaFolder/index.js`,
+	bundle: true,
+	inject: ['pathTo/shims.js'],
+	platform: 'node'
+}
+```
+
 ## Changelog
 
 [The Changelog for this package is available on GitHub](https://github.com/sveltejs/kit/blob/master/packages/adapter-vercel/CHANGELOG.md).

packages/adapter-vercel/index.js

@@ -3,7 +3,16 @@ import { join } from 'path';
 import { fileURLToPath } from 'url';
 import esbuild from 'esbuild';
 
-export default function () {
+/**
+ * @typedef {import('esbuild').BuildOptions} BuildOptions
+ */
+
+/**
+ * @param {{
+ *   esbuild?: (defaultOptions: BuildOptions) => Promise<BuildOptions> | BuildOptions;
+ * }} options
+ **/
+export default function (options = { esbuild: (opts) => opts }) {
 	/** @type {import('@sveltejs/kit').Adapter} */
 	const adapter = {
 		name: '@sveltejs/adapter-vercel',
@@ -27,14 +36,16 @@ export default function () {
 			utils.log.minor('Generating serverless function...');
 			utils.copy(join(files, 'entry.js'), '.svelte-kit/vercel/entry.js');
 
-			await esbuild.build({
+			const buildOptions = await options.esbuild({
 				entryPoints: ['.svelte-kit/vercel/entry.js'],
 				outfile: join(dirs.lambda, 'index.js'),
 				bundle: true,
 				inject: [join(files, 'shims.js')],
 				platform: 'node'
 			});
 
+			await esbuild.build(buildOptions);
+
 			writeFileSync(join(dirs.lambda, 'package.json'), JSON.stringify({ type: 'commonjs' }));
 
 			utils.log.minor('Prerendering static pages...');