feat(ssr): support external true

.eslintrc.cjs

@@ -148,7 +148,7 @@ module.exports = defineConfig({
       }
     },
     {
-      files: ['playground/**'],
+      files: ['playground/**', '**/__tests__/**'],
       rules: {
         'node/no-extraneous-import': 'off',
         'node/no-extraneous-require': 'off',

docs/config/ssr-options.md

@@ -2,17 +2,17 @@
 
 ## ssr.external
 
-- **Type:** `string[]`
+- **Type:** `string[] | true`
 - **Related:** [SSR Externals](/guide/ssr#ssr-externals)
 
-Force externalize dependencies for SSR.
+Externalize dependencies for SSR. By default, all dependencies are externalized, except linked dependencies for HMR. This can opted-out by adding the dependency to this option, or set `true` to force externalize all dependencies.
 
 ## ssr.noExternal
 
 - **Type:** `string | RegExp | (string | RegExp)[] | true`
 - **Related:** [SSR Externals](/guide/ssr#ssr-externals)
 
-Prevent listed dependencies from being externalized for SSR. If `true`, no dependencies are externalized.
+Prevent listed dependencies from being externalized for SSR. If `true`, no dependencies are externalized. If a dependency is explicitly defined in `ssr.external`, it will take priority and be externalized along with its transitive dependencies.
 
 ## ssr.target
 

packages/vite/src/node/ssr/__tests__/fixtures/cjs-ssr-dep/index.js

@@ -0,0 +1,3 @@
+module.exports = {
+  hello: () => 'world'
+}

packages/vite/src/node/ssr/__tests__/fixtures/cjs-ssr-dep/package.json

@@ -0,0 +1,5 @@
+{
+  "name": "@vitejs/cjs-ssr-dep",
+  "private": true,
+  "version": "0.0.0"
+}

packages/vite/src/node/ssr/__tests__/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "@vitejs/unit-ssr",
+  "private": true,
+  "version": "0.0.0",
+  "dependencies": {
+    "@vitejs/cjs-ssr-dep": "link:./fixtures/cjs-ssr-dep"
+  }
+}

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

@@ -1,6 +1,33 @@
-import { expect, test } from 'vitest'
-import { stripNesting } from '../ssrExternal'
+import { fileURLToPath } from 'node:url'
+import { describe, expect, test } from 'vitest'
+import type { SSROptions } from '..'
+import { resolveConfig } from '../../config'
+import { createIsConfiguredAsSsrExternal, stripNesting } from '../ssrExternal'
 
 test('stripNesting', async () => {
   expect(stripNesting(['c', 'p1>c1', 'p2 > c2'])).toEqual(['c', 'c1', 'c2'])
 })
+
+describe('createIsConfiguredAsSsrExternal', () => {
+  test('default', async () => {
+    const isExternal = await createIsExternal()
+    expect(isExternal('@vitejs/cjs-ssr-dep')).toBe(false)
+  })
+
+  test('force external', async () => {
+    const isExternal = await createIsExternal({ external: true })
+    expect(isExternal('@vitejs/cjs-ssr-dep')).toBe(true)
+  })
+})
+
+async function createIsExternal(ssrConfig?: SSROptions) {
+  const resolvedConfig = await resolveConfig(
+    {
+      configFile: false,
+      root: fileURLToPath(new URL('./', import.meta.url)),
+      ssr: ssrConfig
+    },
+    'serve'
+  )
+  return createIsConfiguredAsSsrExternal(resolvedConfig)
+}

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

@@ -7,7 +7,7 @@ export type SsrDepOptimizationOptions = DepOptimizationConfig
 
 export interface SSROptions {
   noExternal?: string | RegExp | (string | RegExp)[] | true
-  external?: string[]
+  external?: string[] | true
   /**
    * Define the target for the ssr build. The browser field in package.json
    * is ignored for node but used if webworker is the target

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

@@ -46,10 +46,12 @@ export function cjsSsrResolveExternals(
 
   const ssrExternals: Set<string> = new Set()
   const seen: Set<string> = new Set()
-  ssrConfig?.external?.forEach((id) => {
-    ssrExternals.add(id)
-    seen.add(id)
-  })
+  if (Array.isArray(ssrConfig?.external)) {
+    ssrConfig.external.forEach((id) => {
+      ssrExternals.add(id)
+      seen.add(id)
+    })
+  }
 
   cjsSsrCollectExternals(
     config.root,
@@ -156,34 +158,35 @@ export function createIsConfiguredAsSsrExternal(
   // Returns true if it is configured as external, false if it is filtered
   // by noExternal and undefined if it isn't affected by the explicit config
   return (id: string) => {
-    const { ssr } = config
-    if (ssr) {
-      if (
-        // If this id is defined as external, force it as external
-        // Note that individual package entries are allowed in ssr.external
-        ssr.external?.includes(id)
-      ) {
-        return true
-      }
-      const pkgName = getNpmPackageName(id)
-      if (!pkgName) {
-        return isExternalizable(id)
-      }
-      if (
-        // A package name in ssr.external externalizes every
-        // externalizable package entry
-        ssr.external?.includes(pkgName)
-      ) {
-        return isExternalizable(id, true)
-      }
-      if (typeof noExternal === 'boolean') {
-        return !noExternal
-      }
-      if (noExternalFilter && !noExternalFilter(pkgName)) {
-        return false
-      }
+    if (
+      // If this id is defined as external, force it as external
+      // Note that individual package entries are allowed in ssr.external
+      ssr.external !== true &&
+      ssr.external?.includes(id)
+    ) {
+      return true
+    }
+    const pkgName = getNpmPackageName(id)
+    if (!pkgName) {
+      return isExternalizable(id)
+    }
+    if (
+      // A package name in ssr.external externalizes every
+      // externalizable package entry
+      ssr.external !== true &&
+      ssr.external?.includes(pkgName)
+    ) {
+      return isExternalizable(id, true)
+    }
+    if (typeof noExternal === 'boolean') {
+      return !noExternal
+    }
+    if (noExternalFilter && !noExternalFilter(pkgName)) {
+      return false
     }
-    return isExternalizable(id)
+    // If `ssr.external: true`, all will be externalized by default, regardless if
+    // it's a linked package
+    return isExternalizable(id, ssr.external === true)
   }
 }
 

pnpm-workspace.yaml

@@ -1,3 +1,4 @@
 packages:
   - 'packages/*'
   - 'playground/**'
+  - '**/__tests__/**'