feat(plugin-legacy): add modernTargets option

packages/plugin-legacy/package.json

@@ -55,6 +55,7 @@
   },
   "devDependencies": {
     "acorn": "^8.11.2",
+    "esbuild-plugin-browserslist": "^0.10.0",
     "picocolors": "^1.0.0",
     "vite": "workspace:*"
   }

packages/plugin-legacy/src/index.ts

@@ -24,6 +24,7 @@ import type {
 } from '@babel/core'
 import colors from 'picocolors'
 import browserslist from 'browserslist'
+import { resolveToEsbuildTarget } from 'esbuild-plugin-browserslist'
 import type { Options } from './types'
 import {
   detectModernBrowserCode,
@@ -125,6 +126,7 @@ const prefixedHashInFileNameRE = /\W?\[hash(:\d+)?\]/
 function viteLegacyPlugin(options: Options = {}): Plugin[] {
   let config: ResolvedConfig
   let targets: Options['targets']
+  let modernTargets: Options['modernTargets']
 
   // browsers supporting ESM + dynamic import + import.meta + async generator
   const modernTargetsEsbuild = [
@@ -205,7 +207,9 @@ function viteLegacyPlugin(options: Options = {}): Plugin[] {
           // Vite's default target browsers are **not** the same.
           // See https://github.com/vitejs/vite/pull/10052#issuecomment-1242076461
           overriddenBuildTarget = config.build.target !== undefined
-          config.build.target = modernTargetsEsbuild
+          config.build.target = options.modernTargets
+            ? resolveToEsbuildTarget(browserslist(options.modernTargets))
+            : modernTargetsEsbuild
         }
       }
 
@@ -322,6 +326,10 @@ function viteLegacyPlugin(options: Options = {}): Plugin[] {
         'last 2 versions and not dead, > 0.3%, Firefox ESR'
       isDebug && console.log(`[@vitejs/plugin-legacy] targets:`, targets)
 
+      modernTargets = options.modernTargets || modernTargetsBabel
+      isDebug &&
+        console.log(`[@vitejs/plugin-legacy] modernTargets:`, modernTargets)
+
       const getLegacyOutputFileName = (
         fileNames:
           | string
@@ -394,7 +402,7 @@ function viteLegacyPlugin(options: Options = {}): Plugin[] {
           genModern
         ) {
           // analyze and record modern polyfills
-          await detectPolyfills(raw, modernTargetsBabel, modernPolyfills)
+          await detectPolyfills(raw, modernTargets, modernPolyfills)
         }
 
         const ms = new MagicString(raw)

packages/plugin-legacy/src/types.ts

@@ -3,6 +3,10 @@ export interface Options {
    * default: 'defaults'
    */
   targets?: string | string[] | { [key: string]: string }
+  /**
+   * default: 'edge>=80, firefox>=72, chrome>=80, safari>=13.1, chromeAndroid>=80, iOS>=13.1'
+   */
+  modernTargets?: string | string[]
   /**
    * default: true
    */