From aebaa05628325227366b55af3dfe9ab1b3843085 Mon Sep 17 00:00:00 2001
From: Vben <anncwb@126.com>
Date: Mon, 22 Mar 2021 16:40:52 +0800
Subject: [PATCH 1/2] fix(plugin-legacy): respect custom filenames format
 output fix #2356

---
 packages/plugin-legacy/index.js | 39 ++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/packages/plugin-legacy/index.js b/packages/plugin-legacy/index.js
index 3eb0e863bf7bb1..d7a634c2c02bbb 100644
--- a/packages/plugin-legacy/index.js
+++ b/packages/plugin-legacy/index.js
@@ -150,6 +150,35 @@ function viteLegacyPlugin(options = {}) {
         return
       }
 
+      /**
+       * @param {string|((chunkInfo: import('rollup').PreRenderedChunk)=>string)} fileNames
+       * @param {string?} defaultFileName
+       */
+      const getLegacyOutputFileName = (
+        fileNames,
+        defaultFileName = '[name]-legacy.[hash].js'
+      ) => {
+        if (!fileNames) {
+          return path.posix.join(config.build.assetsDir, defaultFileName)
+        }
+
+        // does not support custom functions.
+        if (typeof fileNames === 'function') {
+          throw new Error(
+            `@vitejs/plugin-legacy rollupOptions.output.entryFileNames and rollupOptions.output.chunkFileNames` +
+              ` does not currently support the function format.`
+          )
+        }
+
+        let fileName = defaultFileName
+        // Custom string file return format.
+        if (fileNames && typeof fileNames === 'string') {
+          fileName = fileNames.replace(/\[name\]/, '[name]-legacy')
+        }
+
+        return path.posix.join(config.build.assetsDir, fileName)
+      }
+
       /**
        * @param {import('rollup').OutputOptions} options
        * @returns {import('rollup').OutputOptions}
@@ -158,14 +187,8 @@ function viteLegacyPlugin(options = {}) {
         return {
           ...options,
           format: 'system',
-          entryFileNames: path.posix.join(
-            config.build.assetsDir,
-            `[name]-legacy.[hash].js`
-          ),
-          chunkFileNames: path.posix.join(
-            config.build.assetsDir,
-            `[name]-legacy.[hash].js`
-          )
+          entryFileNames: getLegacyOutputFileName(options.entryFileNames),
+          chunkFileNames: getLegacyOutputFileName(options.chunkFileNames)
         }
       }
 

From 971e3bcc47716de2317d956f44ef521bb3e7a0cc Mon Sep 17 00:00:00 2001
From: Vben <anncwb@126.com>
Date: Mon, 22 Mar 2021 22:43:06 +0800
Subject: [PATCH 2/2] chore: supplement legacy playground example

---
 packages/playground/legacy/package.json           |  1 +
 .../legacy/vite.config-custom-filename.js         | 15 +++++++++++++++
 packages/plugin-legacy/index.js                   |  4 ++--
 3 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 packages/playground/legacy/vite.config-custom-filename.js

diff --git a/packages/playground/legacy/package.json b/packages/playground/legacy/package.json
index 89a5130f8e9eb9..4c65846365eabe 100644
--- a/packages/playground/legacy/package.json
+++ b/packages/playground/legacy/package.json
@@ -5,6 +5,7 @@
   "scripts": {
     "dev": "vite",
     "build": "vite build --debug legacy",
+    "build:custom-filename": "vite --config ./vite.config-custom-filename.js build  --debug legacy",
     "debug": "node --inspect-brk ../../vite/bin/vite",
     "serve": "vite preview"
   },
diff --git a/packages/playground/legacy/vite.config-custom-filename.js b/packages/playground/legacy/vite.config-custom-filename.js
new file mode 100644
index 00000000000000..9a96133b015588
--- /dev/null
+++ b/packages/playground/legacy/vite.config-custom-filename.js
@@ -0,0 +1,15 @@
+const legacy = require('@vitejs/plugin-legacy').default
+
+module.exports = {
+  plugins: [legacy()],
+  build: {
+    manifest: true,
+    minify: false,
+    rollupOptions: {
+      output: {
+        entryFileNames: `assets/[name].js`,
+        chunkFileNames: `assets/[name].js`
+      }
+    }
+  }
+}
diff --git a/packages/plugin-legacy/index.js b/packages/plugin-legacy/index.js
index d7a634c2c02bbb..b019d070001f0b 100644
--- a/packages/plugin-legacy/index.js
+++ b/packages/plugin-legacy/index.js
@@ -166,7 +166,7 @@ function viteLegacyPlugin(options = {}) {
         if (typeof fileNames === 'function') {
           throw new Error(
             `@vitejs/plugin-legacy rollupOptions.output.entryFileNames and rollupOptions.output.chunkFileNames` +
-              ` does not currently support the function format.`
+              ` does not support the function format.`
           )
         }
 
@@ -176,7 +176,7 @@ function viteLegacyPlugin(options = {}) {
           fileName = fileNames.replace(/\[name\]/, '[name]-legacy')
         }
 
-        return path.posix.join(config.build.assetsDir, fileName)
+        return fileName
       }
 
       /**