feat: enable experimentalOptimizer

docs/config/index.md

@@ -113,19 +113,16 @@ Handling for dependencies resolution.
 - **Version:** Since Vitest 0.29.0
 - **See also:** [Dep Optimization Options](https://vitejs.dev/config/dep-optimization-options.html)
 
-::: warning
-This feature is temporarily disabled since Vitest 0.30.0.
-:::
-
 Enable dependency optimization. If you have a lot of tests, this might improve their performance.
 
 For `jsdom` and `happy-dom` environments, when Vitest will encounter the external library, it will be bundled into a single file using esbuild and imported as a whole module. This is good for several reasons:
 
 - Importing packages with a lot of imports is expensive. By bundling them into one file we can save a lot of time
 - Importing UI libraries is expensive because they are not meant to run inside Node.js
 - Your `alias` configuration is now respected inside bundled packages
+- Code in your tests is running closer to how it's running in the browser
 
-You can opt-out of this behavior for certain packages with `exclude` option. You can read more about available options in [Vite](https://vitejs.dev/config/dep-optimization-options.html) docs.
+Be aware that only packages in `deps.experimentalOptimizer.include` option are bundled (some plugins populate this automatically, like Svelte). You can read more about available options in [Vite](https://vitejs.dev/config/dep-optimization-options.html) docs.
 
 This options also inherits your `optimizeDeps` configuration. If you redefine `include`/`exclude`/`entries` option in `deps.experimentalOptimizer` it will overwrite your `optimizeDeps` when running tests.
 

packages/vitest/src/node/error.ts

@@ -169,9 +169,12 @@ function printModuleWarningForPackage(logger: Logger, path: string, name: string
 + c.green(`export default {
   test: {
     deps: {
-      inline: [
-        ${c.yellow(c.bold(`"${name}"`))}
-      ]
+      experimentalOptimizer: {
+        enabled: true,
+        include: [
+          ${c.yellow(c.bold(`"${name}"`))}
+        ]
+      }
     }
   }
 }\n`)))

packages/vitest/src/node/plugins/index.ts

@@ -1,3 +1,5 @@
+import { builtinModules } from 'node:module'
+import { version as viteVersion } from 'vite'
 import type { UserConfig as ViteConfig, Plugin as VitePlugin } from 'vite'
 import { relative } from 'pathe'
 import { configDefaults } from '../../defaults'
@@ -134,49 +136,32 @@ export async function VitestPlugin(options: UserConfig = {}, ctx = new Vitest('t
         }
 
         const optimizeConfig: Partial<ViteConfig> = {}
-        // TODO: optimizer is temporary disabled, until Vite provides "optimzier.byDefault" option
-        // const optimizer = preOptions.deps?.experimentalOptimizer
-        // if (!optimizer?.enabled) {
-        optimizeConfig.cacheDir = undefined
-        optimizeConfig.optimizeDeps = {
-          // experimental in Vite >2.9.2, entries remains to help with older versions
-          disabled: true,
-          entries: [],
+        const optimizer = preOptions.deps?.experimentalOptimizer
+        const [major, minor] = viteVersion.split('.').map(Number)
+        const allowed = major >= 5 || (major === 4 && minor >= 3)
+        if (!allowed && optimizer?.enabled === true)
+          console.warn(`Vitest: "deps.experimentalOptimizer" is only available in Vite >= 4.3.0, current Vite version: ${viteVersion}`)
+        if (!allowed || optimizer?.enabled !== true) {
+          optimizeConfig.cacheDir = undefined
+          optimizeConfig.optimizeDeps = {
+            // experimental in Vite >2.9.2, entries remains to help with older versions
+            disabled: true,
+            entries: [],
+          }
+        }
+        else {
+          const cacheDir = preOptions.cache !== false ? preOptions.cache?.dir : null
+          optimizeConfig.cacheDir = cacheDir ?? 'node_modules/.vitest'
+          optimizeConfig.optimizeDeps = {
+            ...viteConfig.optimizeDeps,
+            ...optimizer,
+            noDiscovery: true,
+            disabled: false,
+            entries: [],
+            exclude: ['vitest', ...builtinModules, ...(optimizer.exclude || viteConfig.optimizeDeps?.exclude || [])],
+            include: (optimizer.include || viteConfig.optimizeDeps?.include || []).filter((n: string) => n !== 'vitest'),
+          }
         }
-        // }
-        // else {
-        //   const root = config.root || process.cwd()
-        //   // TODO: add support for experimental optimizer
-        //   const entries = []
-        //   // const [...entries] = await ctx.globAllTestFiles(preOptions as ResolvedConfig, preOptions.dir || root)
-        //   if (preOptions?.setupFiles) {
-        //     const setupFiles = toArray(preOptions.setupFiles).map((file: string) =>
-        //       normalize(
-        //         resolveModule(file, { paths: [root] })
-        //             ?? resolve(root, file),
-        //       ),
-        //     )
-        //     entries.push(...setupFiles)
-        //   }
-        //   const cacheDir = preOptions.cache !== false ? preOptions.cache?.dir : null
-        //   optimizeConfig.cacheDir = cacheDir ?? 'node_modules/.vitest'
-        //   optimizeConfig.optimizeDeps = {
-        //     ...viteConfig.optimizeDeps,
-        //     ...optimizer,
-        //     disabled: false,
-        //     entries: [...(viteConfig.optimizeDeps?.entries || []), ...entries],
-        //     exclude: ['vitest', ...builtinModules, ...(optimizer.exclude || viteConfig.optimizeDeps?.exclude || [])],
-        //     include: (optimizer.include || viteConfig.optimizeDeps?.include || []).filter((n: string) => n !== 'vitest'),
-        //   }
-        //   // Vite throws an error that it cannot rename "deps_temp", but optimization still works
-        //   // let's not show this error to users
-        //   const { error: logError } = console
-        //   console.error = (...args) => {
-        //     if (typeof args[0] === 'string' && args[0].includes('/deps_temp'))
-        //       return
-        //     return logError(...args)
-        //   }
-        // }
         Object.assign(config, optimizeConfig)
 
         return config

packages/vitest/src/node/plugins/workspace.ts

@@ -1,5 +1,7 @@
+import { builtinModules } from 'node:module'
 import { dirname, relative } from 'pathe'
 import type { UserConfig as ViteConfig, Plugin as VitePlugin } from 'vite'
+import { version as viteVersion } from 'vite'
 import { configDefaults } from '../../defaults'
 import { generateScopedClassName } from '../../integrations/css/css-modules'
 import { deepMerge } from '../../utils/base'
@@ -116,6 +118,35 @@ export function WorkspaceVitestPlugin(project: WorkspaceProject, options: Worksp
           }
         }
 
+        const optimizeConfig: Partial<ViteConfig> = {}
+        const optimizer = testConfig.deps?.experimentalOptimizer
+        const [major, minor] = viteVersion.split('.').map(Number)
+        const allowed = major >= 5 || (major === 4 && minor >= 3)
+        if (!allowed && optimizer?.enabled === true)
+          console.warn(`Vitest: "deps.experimentalOptimizer" is only available in Vite >= 4.3.0, current Vite version: ${viteVersion}`)
+        if (!allowed || optimizer?.enabled !== true) {
+          optimizeConfig.cacheDir = undefined
+          optimizeConfig.optimizeDeps = {
+            // experimental in Vite >2.9.2, entries remains to help with older versions
+            disabled: true,
+            entries: [],
+          }
+        }
+        else {
+          const cacheDir = testConfig.cache !== false ? testConfig.cache?.dir : null
+          optimizeConfig.cacheDir = cacheDir ?? 'node_modules/.vitest'
+          optimizeConfig.optimizeDeps = {
+            ...viteConfig.optimizeDeps,
+            ...optimizer,
+            noDiscovery: true,
+            disabled: false,
+            entries: [],
+            exclude: ['vitest', ...builtinModules, ...(optimizer.exclude || viteConfig.optimizeDeps?.exclude || [])],
+            include: (optimizer.include || viteConfig.optimizeDeps?.include || []).filter((n: string) => n !== 'vitest'),
+          }
+        }
+        Object.assign(config, optimizeConfig)
+
         return config
       },
       async configureServer(server) {

packages/vitest/src/types/config.ts

@@ -74,7 +74,7 @@ interface DepsOptions {
   /**
    * Enable dependency optimization. This can improve the performance of your tests.
    */
-  experimentalOptimizer?: Omit<DepOptimizationConfig, 'disabled'> & {
+  experimentalOptimizer?: Omit<DepOptimizationConfig, 'disabled' | 'noDiscovery'> & {
     enabled: boolean
   }
   /**