Compression

Davaux has built-in response compression for both dynamic routes and files served from public/. Enable it via performance.compress in davaux.config.ts. No package to install.

Basic usage

// davaux.config.ts
import { defineConfig } from 'davaux/config'

export default defineConfig({
  performance: {
    compress: true,
  },
})

Brotli is used when the client supports it, gzip otherwise, deflate as a last resort — negotiated automatically from the Accept-Encoding request header.

With options

export default defineConfig({
  performance: {
    compress: {
      encodings: ['br', 'gzip', 'deflate'], // preference order — default
      filter: (contentType) => contentType.startsWith('text/'),
    },
  },
})

Limit to gzip only

Useful when deploying behind infrastructure that doesn't support brotli:

performance: { compress: { encodings: ['gzip'] } }

What gets compressed

By default the following content types are compressed:

How it works

Compression applies at two levels:

Dynamic routes — At the start of each request, Davaux wraps res.writeHead, res.write, and res.end. When the route or middleware calls writeHead, the Content-Type is inspected to decide whether to compress. If yes, subsequent writes are piped through a Node.js zlib transform stream (brotli at quality 4, gzip/deflate at level 6). Content-Length is removed and Content-Encoding + Vary: Accept-Encoding are set. Streaming responses (ctx.defer()) are compressed chunk-by-chunk automatically.

Static files — Files served from public/ and /_davaux/ (islands, client bundle, styles) are piped through the same zlib streams before being written to the socket.

When to skip it

If you deploy behind a reverse proxy (nginx, Caddy, AWS CloudFront) that handles compression, leave compress unset. The proxy approach offloads CPU from Node.js and typically caches compressed responses — enabling both would waste CPU without benefit. Most proxies detect an existing Content-Encoding header and skip re-compression, but there is no upside to doing the work twice.