rolldown · sxzz · Apr 7, 2026 · Apr 7, 2026
diff --git a/dts.snapshot.json b/dts.snapshot.json
@@ -1,5 +1,5 @@
 {
-  "config-!~{00c}~.d.mts": {
+  "config-!~{00d}~.d.mts": {
     "defineConfig": "declare function defineConfig(_: UserConfigExport): UserConfigExport",
     "mergeConfig": "declare function mergeConfig(_: InlineConfig, ...overrides: InlineConfig[]): InlineConfig",
     "resolveUserConfig": "declare function resolveUserConfig(_: UserConfig, _: InlineConfig): Promise<ResolvedConfig[]>"
@@ -13,6 +13,29 @@
       "mergeConfig"
     ]
   },
+  "index-!~{00b}~.d.mts": {
+    "Arrayable": "type Arrayable<T> = T | T[]",
+    "Awaitable": "type Awaitable<T> = T | Promise<T>",
+    "globalLogger": "Logger",
+    "Logger": "interface Logger {\n level: LogLevel\n options?: LoggerOptions\n info: (...args: any[]) => void\n warn: (...args: any[]) => void\n warnOnce: (...args: any[]) => void\n error: (...args: any[]) => void\n success: (...args: any[]) => void\n clearScreen: (_: LogType) => void\n}",
+    "LoggerOptions": "interface LoggerOptions {\n allowClearScreen?: boolean\n customLogger?: Logger\n console?: Console\n failOnWarn?: boolean\n}",
+    "LogLevel": "type LogLevel = LogType | 'silent'",
+    "LogType": "type LogType = 'error' | 'warn' | 'info'",
+    "MarkPartial": "type MarkPartial<T, K extends keyof T> = Omit<Required<T>, K> & Partial<Pick<T, K>>",
+    "Overwrite": "type Overwrite<T, U> = Omit<T, keyof U> & U",
+    "PackageJson": "interface PackageJson {\n name?: string\n version?: string\n description?: string\n keywords?: string[]\n homepage?: string\n bugs?: string | { url?: string; email?: string }\n license?: string\n repository?: string | { type: string; url: string; directory?: string }\n scripts?: PackageJsonScripts\n private?: boolean\n author?: PackageJsonPerson\n contributors?: PackageJsonPerson[]\n funding?: PackageJsonFunding | PackageJsonFunding[]\n files?: string[]\n main?: string\n browser?: string | Record<string, string | false>\n unpkg?: string\n bin?: string | Record<string, string>\n man?: string | string[]\n dependencies?: Record<string, string>\n devDependencies?: Record<string, string>\n optionalDependencies?: Record<string, string>\n peerDependencies?: Record<string, string>\n types?: string\n typings?: string\n module?: string\n type?: 'module' | 'commonjs'\n exports?: PackageJsonExports\n imports?: Record<string, string | Record<string, string>>\n workspaces?: string[] | { packages?: string[]; nohoist?: string[] }\n typesVersions?: Record<string, Record<string, string[]>>\n os?: string[]\n cpu?: string[]\n publishConfig?: { registry?: string; tag?: string; access?: 'public' | 'restricted'; executableFiles?: string[]; directory?: string; linkDirectory?: boolean } & Pick<PackageJson, 'bin' | 'main' | 'exports' | 'types' | 'typings' | 'module' | 'browser' | 'unpkg' | 'typesVersions' | 'os' | 'cpu'>\n packageManager?: string\n [key: string]: any\n}",
+    "PackageJsonCommonScripts": "type PackageJsonCommonScripts = 'build' | 'coverage' | 'deploy' | 'dev' | 'format' | 'lint' | 'preview' | 'release' | 'typecheck' | 'watch'",
+    "PackageJsonExportKey": "type PackageJsonExportKey = '.' | 'import' | 'require' | 'types' | 'node' | 'browser' | 'default' | (string & {})",
+    "PackageJsonExports": "type PackageJsonExports = string | PackageJsonExportsObject | Array<string | PackageJsonExportsObject>",
+    "PackageJsonExportsObject": "type PackageJsonExportsObject = { [P in PackageJsonExportKey]?: string | PackageJsonExportsObject | Array<string | PackageJsonExportsObject> }",
+    "PackageJsonFunding": "type PackageJsonFunding = string | { url: string; type?: string }",
+    "PackageJsonNpmLifeCycleScripts": "type PackageJsonNpmLifeCycleScripts = 'dependencies' | 'prepublishOnly' | PackageJsonScriptWithPreAndPost<'install' | 'pack' | 'prepare' | 'publish' | 'restart' | 'start' | 'stop' | 'test' | 'version'>",
+    "PackageJsonPerson": "type PackageJsonPerson = string | { name: string; email?: string; url?: string }",
+    "PackageJsonPnpmLifeCycleScripts": "type PackageJsonPnpmLifeCycleScripts = 'pnpm:devPreinstall'",
+    "PackageJsonScriptName": "type PackageJsonScriptName = PackageJsonCommonScripts | PackageJsonNpmLifeCycleScripts | PackageJsonPnpmLifeCycleScripts | (string & {})",
+    "PackageJsonScripts": "type PackageJsonScripts = { [P in PackageJsonScriptName]?: string }",
+    "PackageJsonScriptWithPreAndPost": "type PackageJsonScriptWithPreAndPost<S extends string> = S | `${'pre' | 'post'}${S}`"
+  },
   "index.d.mts": {
     "build": "declare function build(_: InlineConfig): Promise<TsdownBundle[]>",
     "buildWithConfigs": "declare function buildWithConfigs(_: ResolvedConfig[], _: string[], _: () => void): Promise<TsdownBundle[]>",
@@ -71,6 +94,7 @@
     ]
   },
   "internal.d.mts": {
+    "expandBaselineTarget": "declare function expandBaselineTarget(_: string[]): string[]",
     "fsExists": "declare function fsExists(_: string): Promise<boolean>",
     "fsRemove": "declare function fsRemove(_: string): Promise<void>",
     "importWithError": "declare function importWithError<T>(_: string): Promise<T>",
@@ -80,24 +104,14 @@
       "Logger",
       "MarkPartial",
       "Overwrite",
+      "expandBaselineTarget",
       "fsExists",
       "fsRemove",
       "importWithError",
       "resolveComma",
       "toArray"
     ]
   },
-  "logger-!~{00a}~.d.mts": {
-    "Arrayable": "type Arrayable<T> = T | T[]",
-    "Awaitable": "type Awaitable<T> = T | Promise<T>",
-    "globalLogger": "Logger",
-    "Logger": "interface Logger {\n level: LogLevel\n options?: LoggerOptions\n info: (...args: any[]) => void\n warn: (...args: any[]) => void\n warnOnce: (...args: any[]) => void\n error: (...args: any[]) => void\n success: (...args: any[]) => void\n clearScreen: (_: LogType) => void\n}",
-    "LoggerOptions": "interface LoggerOptions {\n allowClearScreen?: boolean\n customLogger?: Logger\n console?: Console\n failOnWarn?: boolean\n}",
-    "LogLevel": "type LogLevel = LogType | 'silent'",
-    "LogType": "type LogType = 'error' | 'warn' | 'info'",
-    "MarkPartial": "type MarkPartial<T, K extends keyof T> = Omit<Required<T>, K> & Partial<Pick<T, K>>",
-    "Overwrite": "type Overwrite<T, U> = Omit<T, keyof U> & U"
-  },
   "plugins.d.mts": {
     "NodeProtocolPlugin": "declare function NodeProtocolPlugin(_: 'strip' | true): Plugin",
     "ShebangPlugin": "declare function ShebangPlugin(_: Logger, _: string, _: string, _: boolean): Plugin",
@@ -113,7 +127,7 @@
   "run.d.mts": {
     "#exports": []
   },
-  "types-!~{00b}~.d.mts": {
+  "types-!~{00c}~.d.mts": {
     "AttwOptions": "interface AttwOptions extends CheckPackageOptions {\n module?: typeof _$_arethetypeswrong_core0\n profile?: 'strict' | 'node16' | 'esm-only'\n level?: 'error' | 'warn'\n ignoreRules?: ('no-resolution' | 'untyped-resolution' | 'false-cjs' | 'false-esm' | 'cjs-resolves-to-esm' | 'fallback-condition' | 'cjs-only-exports-default' | 'named-exports' | 'false-export-default' | 'missing-export-equals' | 'unexpected-module-syntax' | 'internal-resolution-error' | (string & {}))[]\n}",
     "BuildContext": "interface BuildContext {\n options: ResolvedConfig\n hooks: Hookable<TsdownHooks>\n}",
     "ChunkAddon": "type ChunkAddon = ChunkAddonObject | ChunkAddonFunction | string",
@@ -137,18 +151,6 @@
     "OutExtensionContext": "interface OutExtensionContext {\n options: InputOptions\n format: NormalizedFormat\n pkgType?: PackageType\n}",
     "OutExtensionFactory": "type OutExtensionFactory = (_: OutExtensionContext) => OutExtensionObject | undefined",
     "OutExtensionObject": "interface OutExtensionObject {\n js?: string\n dts?: string\n}",
-    "PackageJson": "interface PackageJson {\n name?: string\n version?: string\n description?: string\n keywords?: string[]\n homepage?: string\n bugs?: string | { url?: string; email?: string }\n license?: string\n repository?: string | { type: string; url: string; directory?: string }\n scripts?: PackageJsonScripts\n private?: boolean\n author?: PackageJsonPerson\n contributors?: PackageJsonPerson[]\n funding?: PackageJsonFunding | PackageJsonFunding[]\n files?: string[]\n main?: string\n browser?: string | Record<string, string | false>\n unpkg?: string\n bin?: string | Record<string, string>\n man?: string | string[]\n dependencies?: Record<string, string>\n devDependencies?: Record<string, string>\n optionalDependencies?: Record<string, string>\n peerDependencies?: Record<string, string>\n types?: string\n typings?: string\n module?: string\n type?: 'module' | 'commonjs'\n exports?: PackageJsonExports\n imports?: Record<string, string | Record<string, string>>\n workspaces?: string[] | { packages?: string[]; nohoist?: string[] }\n typesVersions?: Record<string, Record<string, string[]>>\n os?: string[]\n cpu?: string[]\n publishConfig?: { registry?: string; tag?: string; access?: 'public' | 'restricted'; executableFiles?: string[]; directory?: string; linkDirectory?: boolean } & Pick<PackageJson, 'bin' | 'main' | 'exports' | 'types' | 'typings' | 'module' | 'browser' | 'unpkg' | 'typesVersions' | 'os' | 'cpu'>\n packageManager?: string\n [key: string]: any\n}",
-    "PackageJsonCommonScripts": "type PackageJsonCommonScripts = 'build' | 'coverage' | 'deploy' | 'dev' | 'format' | 'lint' | 'preview' | 'release' | 'typecheck' | 'watch'",
-    "PackageJsonExportKey": "type PackageJsonExportKey = '.' | 'import' | 'require' | 'types' | 'node' | 'browser' | 'default' | (string & {})",
-    "PackageJsonExports": "type PackageJsonExports = string | PackageJsonExportsObject | Array<string | PackageJsonExportsObject>",
-    "PackageJsonExportsObject": "type PackageJsonExportsObject = { [P in PackageJsonExportKey]?: string | PackageJsonExportsObject | Array<string | PackageJsonExportsObject> }",
-    "PackageJsonFunding": "type PackageJsonFunding = string | { url: string; type?: string }",
-    "PackageJsonNpmLifeCycleScripts": "type PackageJsonNpmLifeCycleScripts = 'dependencies' | 'prepublishOnly' | PackageJsonScriptWithPreAndPost<'install' | 'pack' | 'prepare' | 'publish' | 'restart' | 'start' | 'stop' | 'test' | 'version'>",
-    "PackageJsonPerson": "type PackageJsonPerson = string | { name: string; email?: string; url?: string }",
-    "PackageJsonPnpmLifeCycleScripts": "type PackageJsonPnpmLifeCycleScripts = 'pnpm:devPreinstall'",
-    "PackageJsonScriptName": "type PackageJsonScriptName = PackageJsonCommonScripts | PackageJsonNpmLifeCycleScripts | PackageJsonPnpmLifeCycleScripts | (string & {})",
-    "PackageJsonScripts": "type PackageJsonScripts = { [P in PackageJsonScriptName]?: string }",
-    "PackageJsonScriptWithPreAndPost": "type PackageJsonScriptWithPreAndPost<S extends string> = S | `${'pre' | 'post'}${S}`",
     "PackageJsonWithPath": "interface PackageJsonWithPath extends PackageJson {\n packageJsonPath: string\n}",
     "PackageType": "type PackageType = 'module' | 'commonjs' | undefined",
     "PublintOptions": "interface PublintOptions extends Omit<Options, 'pack' | 'pkgDir'> {\n module?: [typeof _$publint, typeof _$publint_utils0]\n}",

diff --git a/package.json b/package.json
@@ -156,6 +156,7 @@
     "@vitest/coverage-v8": "catalog:dev",
     "@vitest/ui": "catalog:dev",
     "@vueuse/core": "catalog:docs",
+    "baseline-browser-mapping": "catalog:dev",
     "bumpp": "catalog:dev",
     "dedent": "catalog:dev",
     "eslint": "catalog:dev",

diff --git a/packages/css/src/options.ts b/packages/css/src/options.ts
@@ -1,4 +1,5 @@
 import {
+  expandBaselineTarget,
   resolveComma,
   toArray,
   type MarkPartial,
@@ -213,7 +214,7 @@ export function resolveCssOptions(
   } else if (options.target == null) {
     cssTarget = topLevelTarget
   } else {
-    cssTarget = resolveComma(toArray(options.target))
+    cssTarget = expandBaselineTarget(resolveComma(toArray(options.target)))
   }
 
   return {

diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
diff --git a/pnpm-workspace.yaml b/pnpm-workspace.yaml
@@ -21,6 +21,7 @@ catalogs:
     '@typescript/native-preview': 7.0.0-dev.20260405.1
     '@vitest/coverage-v8': ^4.1.2
     '@vitest/ui': ^4.1.2
+    baseline-browser-mapping: ^2.10.16
     bumpp: ^11.0.1
     dedent: ^1.7.2
     eslint: ^10.2.0

diff --git a/scripts/generate-target.ts b/scripts/generate-target.ts
@@ -0,0 +1,35 @@
+import { getCompatibleVersions } from 'baseline-browser-mapping'
+
+// Update on each major release
+const targetDate = '2026-01-01'
+
+// https://oxc.rs/docs/guide/usage/transformer/lowering#target
+const baselineToOxcTargetMap: Record<string, string> = {
+  chrome: 'chrome',
+  edge: 'edge',
+  firefox: 'firefox',
+  safari: 'safari',
+  safari_ios: 'ios',
+}
+
+const oxcSupportedBrowsers = new Set([
+  'chrome',
+  'edge',
+  'firefox',
+  'safari',
+  'ios',
+])
+
+const results = getCompatibleVersions({
+  widelyAvailableOnDate: targetDate,
+})
+
+const oxcTargets = results
+  .map((target) => ({
+    browser: baselineToOxcTargetMap[target.browser],
+    version: target.version,
+  }))
+  .filter((target) => oxcSupportedBrowsers.has(target.browser))
+  .map((target) => `${target.browser}${target.version}`)
+
+console.log('Baseline Widely Available Targets:', oxcTargets)
diff --git a/src/config/types.ts b/src/config/types.ts
@@ -215,7 +215,7 @@ export interface UserConfig {
    * If not set, defaults to the value of `engines.node` in your project's `package.json`.
    * If no `engines.node` field exists, no syntax transformations are applied.
    *
-   * Accepts a single target (e.g., `'es2020'`, `'node18'`), an array of targets, or `false` to disable all transformations.
+   * Accepts a single target (e.g., `'es2020'`, `'node18'`, `'baseline-widely-available'`), an array of targets, or `false` to disable all transformations.
    *
    * @see {@link https://tsdown.dev/options/target#supported-targets} for a list of valid targets and more details.
    *

diff --git a/src/features/target.test.ts b/src/features/target.test.ts
@@ -1,5 +1,21 @@
 import { expect, test } from 'vitest'
-import { resolvePackageTarget } from './target.ts'
+import { expandBaselineTarget, resolvePackageTarget } from './target.ts'
+
+test('expandBaselineTarget', () => {
+  expect(expandBaselineTarget(['baseline-widely-available'])).toEqual([
+    'chrome111',
+    'edge111',
+    'firefox114',
+    'safari16.4',
+    'ios16.4',
+  ])
+
+  expect(expandBaselineTarget(['es2020'])).toEqual(['es2020'])
+
+  expect(expandBaselineTarget(['node18', 'baseline-widely-available'])).toEqual(
+    ['node18', 'chrome111', 'edge111', 'firefox114', 'safari16.4', 'ios16.4'],
+  )
+})
 
 test('resolvePackageTarget', () => {
   expect(testVersion('>= 14')).toMatchInlineSnapshot(`"node14.0.0"`)

diff --git a/src/features/target.ts b/src/features/target.ts
@@ -4,6 +4,21 @@ import type { Logger } from '../utils/logger.ts'
 import type { Ansis } from 'ansis'
 import type { PackageJson } from 'pkg-types'
 
+// Generated by `scripts/generate-target.ts`
+const BASELINE_WIDELY_AVAILABLE_TARGET: string[] = [
+  'chrome111',
+  'edge111',
+  'firefox114',
+  'safari16.4',
+  'ios16.4',
+]
+
+export function expandBaselineTarget(targets: string[]): string[] {
+  return targets.flatMap((t) =>
+    t === 'baseline-widely-available' ? BASELINE_WIDELY_AVAILABLE_TARGET : t,
+  )
+}
+
 export function resolveTarget(
   logger: Logger,
   target: string | string[] | false | undefined,
@@ -24,7 +39,7 @@ export function resolveTarget(
   if (typeof target === 'number') {
     throw new TypeError(`Invalid target: ${target}`)
   }
-  const targets = resolveComma(toArray(target))
+  const targets = expandBaselineTarget(resolveComma(toArray(target)))
   if (targets.length)
     logger.info(
       nameLabel,

diff --git a/src/internal.ts b/src/internal.ts
@@ -1,3 +1,4 @@
+export { expandBaselineTarget } from './features/target.ts'
 export { fsExists, fsRemove } from './utils/fs.ts'
 export { importWithError, resolveComma, toArray } from './utils/general.ts'
 export type { Logger } from './utils/logger.ts'

diff --git a/tests/__snapshots__/target/baseline-widely-available-target.snap.md b/tests/__snapshots__/target/baseline-widely-available-target.snap.md
@@ -0,0 +1,9 @@
+## index.mjs
+
+```mjs
+//#region index.ts
+const foo = a?.b?.();
+//#endregion
+export { foo };
+
+```
diff --git a/tests/target.test.ts b/tests/target.test.ts
@@ -20,6 +20,15 @@ describe('target', () => {
     expect(snapshot).contain('?.')
   })
 
+  test('baseline-widely-available target', async (context) => {
+    const { snapshot } = await testBuild({
+      context,
+      files: { 'index.ts': 'export const foo: number = a?.b?.()' },
+      options: { target: 'baseline-widely-available' },
+    })
+    expect(snapshot).contain('?.')
+  })
+
   test('target: false disables all syntax transformations', async (context) => {
     const { snapshot } = await testBuild({
       context,