'use strict'; var common = require('../common'); var assert = require('assert'); var zlib = require('zlib'); var path = require('path'); var fs = require('fs'); const file = fs.readFileSync(path.resolve(common.fixturesDir, 'person.jpg')); const chunkSize = 12 * 1024; const opts = { level: 9, strategy: zlib.Z_DEFAULT_STRATEGY }; const deflater = zlib.createDeflate(opts); const chunk1 = file.slice(0, chunkSize); const chunk2 = file.slice(chunkSize); const blkhdr = Buffer.from([0x00, 0x5a, 0x82, 0xa5, 0x7d]); const expected = Buffer.concat([blkhdr, chunk2]); let actual; deflater.write(chunk1, function() { deflater.params(0, zlib.Z_DEFAULT_STRATEGY, function() { while (deflater.read()); deflater.end(chunk2, function() { var bufs = [], buf; while (buf = deflater.read()) bufs.push(buf); actual = Buffer.concat(bufs); }); }); while (deflater.read()); }); process.once('exit', function() { assert.deepEqual(actual, expected); });