compress

Negotiates Accept-Encoding and wraps the response stream through the best-matching compressor (Brotli, gzip, or deflate). Compression is skipped automatically for small bodies, non-compressible content types, and no-body status codes.

Pipeline stage: Cross-cutting (place before send)

Import

import { compress } from "@centralping/ergo";

Options

Option	Type	Default	Description
threshold	number	1024	Minimum body size in bytes before compression kicks in
encodings	string[]	['br', 'gzip', 'deflate']	Supported encodings in priority order

Return Value

The middleware modifies the response stream in-place (wrapping res.write and res.end). It does not add to the domain accumulator.

Compression Skipped When

• Status code is 204 or 304
• Content-Type is non-compressible (binary, images, etc.)
• Body is below threshold bytes
• No acceptable encoding found in Accept-Encoding

Error Responses

None. Compression is silently skipped when conditions are not met.

Usage

Standalone

import { compose, compress } from "@centralping/ergo";

const pipeline = compose(
  compress({ threshold: 1024, encodings: ["br", "gzip"] }),
  (req, res, acc) => ({
    response: { body: largePayload },
  }),
);

ergo-router

const router = createRouter({
  defaults: {
    compress: { threshold: 512 },
  },
});

RFC References

• RFC 9110 §12.5.3 — Accept-Encoding

API Reference

See the auto-generated compress API docs.