feat: parameter settings when packaging the library (#2750)

Co-authored-by: Evan You <yyx990803@gmail.com>
Co-authored-by: patak <matias.capeletto@gmail.com>

docs/config/index.md

@@ -502,10 +502,10 @@ export default async ({ command, mode }) => {
 
 ### build.lib
 
-- **Type:** `{ entry: string, name?: string, formats?: ('es' | 'cjs' | 'umd' | 'iife')[] }`
+- **Type:** `{ entry: string, name?: string, formats?: ('es' | 'cjs' | 'umd' | 'iife')[], fileName?: string }`
 - **Related:** [Library Mode](/guide/build#library-mode)
 
-  Build as a library. `entry` is required since the library cannot use HTML as entry. `name` is the exposed global variable and is required when `formats` includes `'umd'` or `'iife'`. Default `formats` are `['es', 'umd']`.
+  Build as a library. `entry` is required since the library cannot use HTML as entry. `name` is the exposed global variable and is required when `formats` includes `'umd'` or `'iife'`. Default `formats` are `['es', 'umd']`. `fileName` is the name of the package file output, default `fileName` is the name option of package.json
 
 ### build.manifest
 

packages/vite/src/node/build.ts

@@ -190,6 +190,7 @@ export interface LibraryOptions {
   entry: string
   name?: string
   formats?: LibraryFormats[]
+  fileName?: string
 }
 
 export type LibraryFormats = 'es' | 'cjs' | 'umd' | 'iife'
@@ -405,7 +406,7 @@ async function doBuild(
         entryFileNames: ssr
           ? `[name].js`
           : libOptions
-          ? `${pkgName}.${output.format || `es`}.js`
+          ? `${libOptions.fileName || pkgName}.${output.format || `es`}.js`
           : path.posix.join(options.assetsDir, `[name].[hash].js`),
         chunkFileNames: libOptions
           ? `[name].js`