feat: improve public asset compression

docs/content/3.config/index.md

@@ -81,8 +81,10 @@ If a `public/` directory is detected, it will be added by default, but you can a
 
 ## `compressPublicAssets`
 
-If enabled, Nitro will generate a precompressed (gzip and brotli) verison of all public assets and prerendered routes
-bigger than 1024 bytes into public directory. Using this option you can support zero overhead asset compression without using a CDN.
+- Default: `{ gzip: false, brotli: false }`
+
+If enabled, Nitro will generate a pre-compressed (gzip and/or brotli) version of supported types of public assets and prerendered routes
+larger than 1024 bytes into the public directory. The best compression level is used. Using this option you can support zero overhead asset compression without using a CDN.
 
 ## `serverAssets`
 

src/rollup/plugins/public-assets.ts

@@ -43,14 +43,26 @@ export function publicAssets (nitro: Nitro): Plugin {
           path: relative(nitro.options.output.serverDir, fullPath)
         }
 
-        if (nitro.options.compressPublicAssets && assetData.length > 1024 && !assetId.endsWith('.map')) {
-          for (const encoding of ['gzip', 'br']) {
+        if (nitro.options.compressPublicAssets && assetData.length > 1024 && !assetId.endsWith('.map') && isTypeCompressible(type)) {
+          const { gzip, brotli } = nitro.options.compressPublicAssets || {} as any
+          const encodings = [gzip !== false && 'gzip', brotli !== false && 'br'].filter(Boolean)
+          for (const encoding of encodings) {
             const suffix = '.' + (encoding === 'gzip' ? 'gz' : 'br')
             const compressedPath = fullPath + suffix
+            const gzipOptions = { level: zlib.constants.Z_BEST_COMPRESSION }
+            const isTextType = type.startsWith('text')
+            const brotliOptions = {
+              [zlib.constants.BROTLI_PARAM_MODE]: isTextType ? zlib.constants.BROTLI_MODE_TEXT : zlib.constants.BROTLI_MODE_GENERIC,
+              [zlib.constants.BROTLI_PARAM_QUALITY]: zlib.constants.BROTLI_MAX_QUALITY,
+              [zlib.constants.BROTLI_PARAM_SIZE_HINT]: assetData.length
+            }
             const compressedBuff: Buffer = await new Promise((resolve, reject) => {
-              zlib[encoding === 'gzip' ? 'gzip' : 'brotliCompress'](assetData,
-                (error, result) => error ? reject(error) : resolve(result)
-              )
+              const cb = (error, result: Buffer) => error ? reject(error) : resolve(result)
+              if (encoding === 'gzip') {
+                zlib.gzip(assetData, gzipOptions, cb)
+              } else {
+                zlib.brotliCompress(assetData, brotliOptions, cb)
+              }
             })
             await fsp.writeFile(compressedPath, compressedBuff)
             assets[assetId + suffix] = {
@@ -107,3 +119,32 @@ export function getAsset (id) {
     }
   }, nitro.vfs)
 }
+
+const isTypeCompressible = (type: string): boolean => {
+  return [
+    'application/javascript',
+    'application/json',
+    'application/manifest+json',
+    'application/rss+xml',
+    'application/vnd.ms-fontobject',
+    'application/x-font-opentype',
+    'application/x-font-truetype',
+    'application/x-font-ttf',
+    'application/x-javascript',
+    'application/xml',
+    'application/xhtml+xml',
+    'font/eot',
+    'font/opentype',
+    'font/otf',
+    'font/truetype',
+    'image/svg+xml',
+    'image/vnd.microsoft.icon',
+    'image/x-icon',
+    'image/x-win-bitmap',
+    'text/css',
+    'text/javascript',
+    'text/plain',
+    'text/xml',
+    'text/x-component'
+  ].includes(type)
+}

src/types/nitro.ts

@@ -87,6 +87,11 @@ export interface DevServerOptions {
   watch: string[]
 }
 
+export interface CompressOptions {
+  gzip?: boolean
+  brotli?: boolean
+}
+
 export interface NitroOptions {
   // Internal
   _config: NitroConfig
@@ -135,7 +140,7 @@ export interface NitroOptions {
   imports: UnimportPluginOptions | false
   plugins: string[]
   virtual: Record<string, string | (() => string | Promise<string>)>
-  compressPublicAssets: boolean
+  compressPublicAssets: boolean | CompressOptions
 
   // Dev
   dev: boolean