Bun v1.1.6

Jarred Sumner · April 28, 2024

Bun is an incredibly fast JavaScript runtime, bundler, transpiler, and package manager — all in one.

Bun v1.1.6 is here! This release fixes 10 bugs (addressing 512 👍 reactions). We've implemented UDP socket support & node:dgram. DataDog and ClickHouseDB now work. We've fixed a regression in node:http from v1.1.5. There are also Node.js compatibility improvements and bugfixes.

We're hiring systems engineers in San Francisco to build the future of JavaScript!

Previous releases

  • v1.1.5 fixes 64 bugs (addressing 101 👍). bun build --compile cross-compile standalone JavaScript & TypeScript executables to other platforms. import any file as text via the type: "text" import attribute. Introduces a new crash reporter. package.json doesn't error with comments or trailing commas. Fixes a bug where bun run --filter exited with 0. Fixes a bug in bun install with file: dependencies. Fixes bugs in node:fs, node:tls, node:crypto, node:readline, node:http, node:worker_threads
  • v1.1.4 fixes 40 bugs (addressing 84 👍 reactions). bun run --filter <workspace> <script> lets you run multiple workspace scripts in parallel. Reinstalls get up to 50% faster in bun install. Important reliability fixes to bun install. bun:sqlite supports using for resource cleanup and has a few bugfixes. Memory leak impacting Next.js Standalone & Web Streams is fixed. Node.js compatibility improvements fs and child_process. Fix for "Connection closed" in fetch(). A few bugfixes for Bundows.
  • v1.1.0 Bundows. Windows support is here!

To install Bun:

curl -fsSL https://bun.sh/install | bash
npm install -g bun
powershell -c "irm bun.sh/install.ps1|iex"
scoop install bun
brew tap oven-sh/bun
brew install bun
docker pull oven/bun
docker run --rm --init --ulimit memlock=-1:-1 oven/bun

To upgrade Bun:

bun upgrade

UDP Sockets

Bun now supports UDP sockets. UDP sockets are a low-level unreliable messaging protocol, often used by production monitoring tools, video/audio streaming tools, and games.

import { udpSocket } from "bun";
const server = await udpSocket({
  socket: {
    data(socket, buf, port, addr) {
      console.log(`message from ${addr}:${port}:`);

const client = await udpSocket({});
client.send("Hello!", server.port, "");

Thanks to @gvilums for implementing UDP socket soupport in Bun!

node:dgram is implemented

node:dgram is the Node.js module for using UDP sockets. Building on top of Bun's new UDP socket support, node:dgram is now implemented. This was one of the most upvoted issues on Bun's GitHub repository.

const dgram = require("dgram");
let count = 0;
const { promise, resolve } = Promise.withResolvers();

const server = dgram.createSocket("udp4");
server.on("message", (msg, {port, address}) => {
  console.log(`server got: ${msg} from ${address}:${port}`);
  if (count++ === 9) process.exit(0);

const client = dgram.createSocket("udp4");
for (let i = 0; i < 10; i++) {
  client.send("hello", 41234, "");
await promise;

Thanks to @gvilums for implementing node:dgram in Bun!

DataDog in Bun

DataDog's dd-trace module now works in Bun. DataDog is a popular infrastructure monitoring tool.

Thanks to @gvilums and @paperdave for getting DataDog to work in Bun!

ClickHouse in Bun

The official Node.js client for ClickHouse now works in Bun.

Thanks to @nektro for getting ClickHouse to work in Bun!

SvelteKit in Bun

A bug impacting fetch when used with SvelteKit has been fixed.

When fetch was called with a Request subclass, Bun would skip calling the method or url getters and instead use the internal method and url properties. Since SvelteKit's Request subclass overrides these properties, this meant we ignored the method property from the Request subclass.

class FooRequest extends Request {
  get method() {
    return "POST";

await fetch(new FooRequest("https://example.com"));
// This would be a GET request instead of a POST request!

This bug has now been fixed, and our test suite has been updated to prevent regressions.

Array#sort gets 15% - 135% faster

This release upgrades to the latest version of JavaScriptCore, and Array.prototype.sort is now 15% - 135% faster in Bun & Safari. Thanks to @Constellation.

❯ bun array-sort.mjs # New
cpu: Apple M3 Max
runtime: bun 1.1.6 (arm64-darwin)

benchmark                            time (avg)             (min … max)       p75       p99      p995
----------------------------------------------------------------------- -----------------------------
Array.sort (64 num, unsorted)    736.22 ns/iter  (673.6 ns … 975.75 ns) 747.02 ns 975.75 ns 975.75 ns
Array.sort (64 num, pre-sorted)  377.94 ns/iter  (370.2 ns … 395.56 ns) 380.33 ns  390.1 ns 395.56 ns

❯ bun-1.1.4 array-sort.mjs # Before
cpu: Apple M3 Max
runtime: bun 1.1.4 (arm64-darwin)

benchmark                            time (avg)             (min … max)       p75       p99      p995
----------------------------------------------------------------------- -----------------------------
Array.sort (64 num, unsorted)      1.14 µs/iter     (1.03 µs … 1.65 µs)   1.19 µs   1.65 µs   1.65 µs
Array.sort (64 num, pre-sorted)    1.07 µs/iter     (1.01 µs … 1.18 µs)   1.08 µs   1.18 µs   1.18 µs

❯ node array-sort.mjs # Node.js, for comparison
cpu: Apple M3 Max
runtime: node v22.0.0 (arm64-darwin)

benchmark                            time (avg)             (min … max)       p75       p99      p995
----------------------------------------------------------------------- -----------------------------
Array.sort (64 num, unsorted)      1.95 µs/iter      (1.8 µs … 2.12 µs)   2.04 µs   2.12 µs   2.12 µs
Array.sort (64 num, pre-sorted)  689.28 ns/iter  (677.4 ns … 719.66 ns) 694.22 ns 719.66 ns 719.66 ns

View microbenchmark

Module._resolveLookupPaths in node:module is implemented

The private Node.js API Module._resolveLookupPaths is now implemented in Bun. This API is used by require-in-the-middle to intercept require calls to instrument module loading.

Warning: when used by dd-trace this may slow down your application's start time.

node:http regression is fixed

A regression in node:http from v1.1.5 is fixed. The regression caused requests with errors to not propagate to the error event correctly. This regression impacted the stripe npm package, amongst others. Thanks to @nektro for fixing this regression!

Fixed: node:http listen callback had wrong this value

A bug where the this value in the listen callback was incorrect has been fixed. The this value is now the server instance, as expected.

Thanks to @nektro for fixing this.

Fixed: cross-compilation extracting bug on Windows

A bug where bun build --compile would incorrectly extract the tarball on Windows has been fixed, thanks to @dylan-conway.

Fixed: error.Unexpected when upgrading bun across devices on Windows

The Windows NT error NOT_SAME_DEVICE was not correctly mapped to the posix error EXDEV, causing an error.Unexpected when upgrading Bun across different drive letters on Windows. This has been fixed.

Fixed: node:dns lookup didn't keep event loop alive on macOS

Previously, the following code would not log hiii on macOS:

const dns = require("dns");

dns.lookup("google.com", (err, address, family) => {

This has been fixed.

The bug was we were not draining microtasks after DNS lookups on macOS were completed. This caused the event loop to be empty, and the process to exit before the callback was called.

Fixed: Bug with TOML & JSON imports

A bug where json and toml imports would go through the CommonJS -> ESM conversion path when they were originally required has been fixed.

The following input:


🔴 Bun v1.1.5 would output (bad):

Module {
  __esModule: true,
  default: {
    hello: "world"
  hello: {
    world: "world"

🟢 Bun v1.1.6 now outputs (good):

  hello: "world",

This should also slightly reduce the memory usage of TOML imports. Previously, we would generate a sourcemap for TOML along with source code, which was unnecessary. Now we just create the objects/values directly without emitting JavaScript source code.

Fixed: memory leak in Bun.write()

When using Bun.write() with large output, the memory for the input string or bytes was not correctly freed. This led to large memory growth over time. This has been fixed, and a memory leak test has been added to prevent this from regressing in the future.

Fixed: Crash in napi_get_date_value

A crash in napi_get_date_value when an unexpected type was passed has been fixed. This crash impacted certain Node Native Addons.

Fixed: Possible crash in HTMLRewriter with Bun.file()

When using HTMLRewriter to transform HTML files on disk with Bun.file(), in certain cases Bun could crash or never fulfill a Promise. This has been fixed.

Fixed: edgecase with --define

A bug where --define when used on a global property would have incorrect output has been fixed, thanks to @dylan-conway.

Thank you to 9 contributors!