feat(ssr): backport ssr.resolve.conditions and ssr.resolve.externalConditions (#14498) (#14668)

Co-authored-by: Marc MacLeod <marbemac@gmail.com>

Author: patak-dev

docs/config/ssr-options.md

@@ -29,3 +29,19 @@ Build target for the SSR server.
 - **Default:** `esm`
 
 Build format for the SSR server. Since Vite v3 the SSR build generates ESM by default. `'cjs'` can be selected to generate a CJS build, but it isn't recommended. The option is left marked as experimental to give users more time to update to ESM. CJS builds require complex externalization heuristics that aren't present in the ESM format.
+
+## ssr.resolve.conditions
+
+- **Type:** `string[]`
+- **Related:** [Resolve Conditions](./shared-options.md#resolve-conditions)
+
+Defaults to the the root [`resolve.conditions`](./shared-options.md#resolve-conditions).
+
+These conditions are used in the plugin pipeline, and only affect non-externalized dependencies during the SSR build. Use `ssr.resolve.externalConditions` to affect externalized imports.
+
+## ssr.resolve.externalConditions
+
+- **Type:** `string[]`
+- **Default:** `[]`
+
+Conditions that are used during ssr import (including `ssrLoadModule`) of externalized dependencies.

docs/guide/ssr.md

@@ -259,6 +259,10 @@ In some cases like `webworker` runtimes, you might want to bundle your SSR build
 - Treat all dependencies as `noExternal`
 - Throw an error if any Node.js built-ins are imported
 
+## SSR Resolve Conditions
+
+By default package entry resolution will use the conditions set in [`resolve.conditions`](../config/shared-options.md#resolve-conditions) for the SSR build. You can use [`ssr.resolve.conditions`](../config/ssr-options.md#ssr-resolve-conditions) and [`ssr.resolve.externalConditions`](../config/ssr-options.md#ssr-resolve-externalconditions) to customize this behavior.
+
 ## Vite CLI
 
 The CLI commands `$ vite dev` and `$ vite preview` can also be used for SSR apps. You can add your SSR middlewares to the development server with [`configureServer`](/guide/api-plugin#configureserver) and to the preview server with [`configurePreviewServer`](/guide/api-plugin#configurepreviewserver).

packages/vite/src/node/plugins/resolve.ts

@@ -173,10 +173,17 @@ export function resolvePlugin(resolveOptions: InternalResolveOptions): Plugin {
       const isRequire: boolean =
         resolveOpts?.custom?.['node-resolve']?.isRequire ?? false
 
+      // end user can configure different conditions for ssr and client.
+      // falls back to client conditions if no ssr conditions supplied
+      const ssrConditions =
+        resolveOptions.ssrConfig?.resolve?.conditions ||
+        resolveOptions.conditions
+
       const options: InternalResolveOptions = {
         isRequire,
         ...resolveOptions,
         scan: resolveOpts?.scan ?? resolveOptions.scan,
+        conditions: ssr ? ssrConditions : resolveOptions.conditions,
       }
 
       const resolvedImports = resolveSubpathImports(

packages/vite/src/node/ssr/index.ts

@@ -8,12 +8,14 @@ export type SsrDepOptimizationOptions = DepOptimizationConfig
 export interface SSROptions {
   noExternal?: string | RegExp | (string | RegExp)[] | true
   external?: string[]
+
   /**
    * Define the target for the ssr build. The browser field in package.json
    * is ignored for node but used if webworker is the target
    * @default 'node'
    */
   target?: SSRTarget
+
   /**
    * Define the format for the ssr build. Since Vite v3 the SSR build generates ESM by default.
    * `'cjs'` can be selected to generate a CJS build, but it isn't recommended. This option is
@@ -33,6 +35,24 @@ export interface SSROptions {
    * @experimental
    */
   optimizeDeps?: SsrDepOptimizationOptions
+
+  resolve?: {
+    /**
+     * Conditions that are used in the plugin pipeline. The default value is the root config's `resolve.conditions`.
+     *
+     * Use this to override the default ssr conditions for the ssr build.
+     *
+     * @default rootConfig.resolve.conditions
+     */
+    conditions?: string[]
+
+    /**
+     * Conditions that are used during ssr import (including `ssrLoadModule`) of externalized dependencies.
+     *
+     * @default []
+     */
+    externalConditions?: string[]
+  }
 }
 
 export interface ResolvedSSROptions extends SSROptions {

packages/vite/src/node/ssr/ssrExternal.ts

@@ -119,11 +119,14 @@ export function createIsConfiguredAsSsrExternal(
     typeof noExternal !== 'boolean' &&
     createFilter(undefined, noExternal, { resolve: false })
 
+  const targetConditions = config.ssr.resolve?.externalConditions || []
+
   const resolveOptions: InternalResolveOptions = {
     ...config.resolve,
     root,
     isProduction: false,
     isBuild: true,
+    conditions: targetConditions,
   }
 
   const isExternalizable = (

packages/vite/src/node/ssr/ssrModuleLoader.ts

@@ -123,19 +123,23 @@ async function instantiateModule(
     isProduction,
     resolve: { dedupe, preserveSymlinks },
     root,
+    ssr,
   } = server.config
 
+  const overrideConditions = ssr.resolve?.externalConditions || []
+
   const resolveOptions: InternalResolveOptionsWithOverrideConditions = {
     mainFields: ['main'],
     browserField: true,
     conditions: [],
-    overrideConditions: ['production', 'development'],
+    overrideConditions: [...overrideConditions, 'production', 'development'],
     extensions: ['.js', '.cjs', '.json'],
     dedupe,
     preserveSymlinks,
     isBuild: false,
     isProduction,
     root,
+    ssrConfig: ssr,
   }
 
   // Since dynamic imports can happen in parallel, we need to
@@ -281,6 +285,8 @@ async function nodeImport(
         ? { ...resolveOptions, tryEsmOnly: true }
         : resolveOptions,
       false,
+      undefined,
+      true,
     )
     if (!resolved) {
       const err: any = new Error(

playground/ssr-conditions/__tests__/serve.ts

@@ -0,0 +1,35 @@
+// this is automatically detected by playground/vitestSetup.ts and will replace
+// the default e2e test serve behavior
+
+import path from 'node:path'
+import kill from 'kill-port'
+import { hmrPorts, ports, rootDir } from '~utils'
+
+export const port = ports['ssr-conditions']
+
+export async function serve(): Promise<{ close(): Promise<void> }> {
+  await kill(port)
+
+  const { createServer } = await import(path.resolve(rootDir, 'server.js'))
+  const { app, vite } = await createServer(rootDir, hmrPorts['ssr-conditions'])
+
+  return new Promise((resolve, reject) => {
+    try {
+      const server = app.listen(port, () => {
+        resolve({
+          // for test teardown
+          async close() {
+            await new Promise((resolve) => {
+              server.close(resolve)
+            })
+            if (vite) {
+              await vite.close()
+            }
+          },
+        })
+      })
+    } catch (e) {
+      reject(e)
+    }
+  })
+}

playground/ssr-conditions/__tests__/ssr-conditions.spec.ts

@@ -0,0 +1,27 @@
+import { expect, test } from 'vitest'
+import { port } from './serve'
+import { page } from '~utils'
+
+const url = `http://localhost:${port}`
+
+test('ssr.resolve.conditions affect non-externalized imports during ssr', async () => {
+  await page.goto(url)
+  expect(await page.textContent('.no-external-react-server')).toMatch(
+    'node.unbundled.js',
+  )
+})
+
+test('ssr.resolve.externalConditions affect externalized imports during ssr', async () => {
+  await page.goto(url)
+  expect(await page.textContent('.external-react-server')).toMatch('edge.js')
+})
+
+test('ssr.resolve settings do not affect non-ssr imports', async () => {
+  await page.goto(url)
+  expect(await page.textContent('.browser-no-external-react-server')).toMatch(
+    'default.js',
+  )
+  expect(await page.textContent('.browser-external-react-server')).toMatch(
+    'default.js',
+  )
+})

playground/ssr-conditions/external/browser.js

@@ -0,0 +1 @@
+export default 'browser.js'

playground/ssr-conditions/external/default.js

@@ -0,0 +1 @@
+export default 'default.js'