var duplex = require('mississippi').duplex var through = require('mississippi').through var zlib = require('zlib') function hasGzipHeader (c) { return c[0] === 0x1F && c[1] === 0x8B && c[2] === 0x08 } module.exports = gunzip function gunzip () { var stream = duplex() var peeker = through(function (chunk, enc, cb) { var newStream = hasGzipHeader(chunk) ? zlib.createGunzip() : through() stream.setReadable(newStream) stream.setWritable(newStream) stream.write(chunk) }) stream.setWritable(peeker) return stream }