Add compression to Elysia Server. Supports gzip, deflate, and brotli.

Note Brotli Compression is only available and supported by Bun v1.1.8 or higher

bun add elysia-compress

This plugin provides a function to automatically compress every Response sent by Elysia Response. Especially on responses in the form of JSON Objects, Text and Stream (Server Sent Events).

Currently, the following encoding tokens are supported, using the first acceptable token in this order:

1. br
2. gzip
3. deflate

If an unsupported encoding is received or if the 'accept-encoding' header is missing, it will not compress the payload.

The plugin automatically decides if a payload should be compressed based on its content-type; if no content type is present, it will assume text/plain. But if you send a response in the form of an Object then it will be detected automatically as application/json

To improve performance, and given data compression is a resource-intensive operation, caching compressed responses can significantly reduce the load on your server. By setting an appropriate TTL (time to live, or how long you want your responses cached), you can ensure that frequently accessed data is served quickly without repeatedly compressing the same content. elysia-compress saves the data in-memory, so it's probably best if you set some sensible defaults (maybe even per-route or group) so as to not increase unnecessarily your memory usage

The global compression hook is enabled by default. To disable it, pass the option { as: 'scoped' } or { as: 'scoped' } You can read in-depth about Elysia Scope on this page

import { Elysia } from 'elysia'
import { compression } from 'elysia-compress'

const app = new Elysia()
  .use(
    compression({
      as: 'scoped',
    }),
  )
  .get('/', () => ({ hello: 'world' }))

The minimum byte size for a response to be compressed. Defaults to 1024.

const app = new Elysia().use(
  compression({
    threshold: 2048,
  }),
)

You can selectively disable response compression by using the x-no-compression header in the request. You can still disable this option by adding disableByHeader: true to options. Default to false

const app = new Elysia().use(
  compression({
    disableByHeader: true,
  }),
)

You can tune compression by setting the brotliOptions and zlibOptions properties. These properties are passed directly to native node zlib methods, so they should match the corresponding class definitions.

const app = new Elysia().use(
  compression({
    brotliOptions: {
      params: {
        [zlib.constants.BROTLI_PARAM_MODE]: zlib.constants.BROTLI_MODE_TEXT, // useful for APIs that primarily return text
        [zlib.constants.BROTLI_PARAM_QUALITY]: 4, // default is 4, max is 11, min is 0
      },
    },
    zlibOptions: {
      level: 6, // default is typically 6, max is 9, min is 0
    },
  }),
)

By default, elysia-compress prioritizes compression as described Usage. You can change that by passing an array of compression tokens to the encodings option:

const app = new Elysia().use(
  compression({
    // Only support gzip and deflate, and prefer deflate to gzip
    encodings: ['deflate', 'gzip'],
  }),
)

You can specify a time-to-live (TTL) for the cache entries to define how long the compressed responses should be cached. The TTL is specified in seconds and defaults to 86400 (24 hours)

const app = new Elysia().use(
  compression({
    TTL: 3600, // Cache TTL of 1 hour
  }),
)

This allows you to control how long the cached compressed responses are stored, helping to balance between performance and memory usage

By default, elysia-compress will not compress responses in Server-Sent Events. If you want to enable compression in Server-Sent Events, you can set the compressStream option to true.

const app = new Elysia().use(
  compression({
    compressStream: true,
  }),
)

This plugins is licensed under the MIT License.