Blog

Bun v1.2.16

Dylan Conway

This release fixes 73 issues (addressing 124 👍), and adds +119 passing Node.js tests. Serve files with Bun.serve through routes, install.linkWorkspacePackages option in bunfig.toml, bun outdated support for catalogs, Bun.hash.rapidhash, node:net compatibility, vm.SyntheticModule support, HTTPParser binding, and memory leak fixes.

To install Bun

curl

curl -fsSL https://bun.sh/install | bash

To upgrade Bun

bun upgrade

Serve files with Bun.serve through routes#

Bun v1.2.16 adds support for returning files for routes, making it easier to serve files directly without needing to manually read and buffer them.

install.linkWorkspacePackages in bunfig.toml#

Bun now supports a linkWorkspacePackages configuration option that controls workspace package linking behavior. This is particularly useful in CI environments where installing pre-built packages from the registry is faster than building from source.

[install]
linkWorkspacePackages = false

When set to false, Bun installs workspace dependencies from the registry instead of linking them locally. The default value is true to maintain backward compatibility. Note that workspace:* protocol is still respected even when this option is disabled.

Thanks to @THEjacob1000 for the contribution!

bun outdated support for catalog dependencies#

bun outdated now supports catalog dependencies, making it easier to check for updates across a monorepo.

package.json

{
  "name": "my-monorepo",
  "workspaces": {
    "packages": ["packages/*"],
    "catalog": {
      "react": "^18.0.0",
      "react-dom": "^18.0.0",
      "typescript": "^4.0.0"
    }
  }
}

packages/app/package.json

{
  "name": "app",
  "dependencies": {
    "react": "catalog:",
    "react-dom": "catalog:",
    "typescript": "catalog:"
  }
}

Running bun outdated for this workspace package now shows updates available for its catalog dependencies:

bun outdated -F app
|----------------------------------------|
| Package    | Current | Update | Latest |
|------------|---------|--------|--------|
| react      | 18.3.1  | 18.3.1 | 19.1.0 |
|------------|---------|--------|--------|
| react-dom  | 18.3.1  | 18.3.1 | 19.1.0 |
|------------|---------|--------|--------|
| typescript | 4.9.5   | 4.9.5  | 5.8.3  |
|----------------------------------------|

Thanks to @juliesaia for the contribution!

Bun.hash.rapidhash#

Bun v1.2.16 adds support for rapidhash in Bun.hash.

const hash = Bun.hash.rapidhash("hello world");
console.log(hash); // 6388527444622164108n

Rapidhash shows competitive performance, especially for larger inputs, making it a great choice for non-cryptographic hashing needs.

Thanks to @joelshepherd for the contribution!

Node.js compatibility improvements#

Major node:net rework#

Bun v1.2.16 includes a rework of the node:net module, significantly improving Node.js compatibility. Highlights:

  • Adds 43 new passing Node.js node:net tests
  • server.maxConnections
  • Improves socket connection callback behavior
  • Fixes TLS upgrade functionality
  • Correctly recognizes custom methods on extended Socket classes
  • socket.localAddress() and socket.remoteAddress() fixed
  • node:net now calls dns.lookup similarly to Node.js
  • net.BlockList support for net.Socket and net.Server

Thanks to @nektro!

vm.SyntheticModule support#

Bun now implements vm.SyntheticModule, enabling creation and evaluation of synthetic modules in the VM context.

import vm from "node:vm";

const module = new vm.SyntheticModule(["x"], function () {
  this.setExport("x", 42);
});

await module.link(() => {});
await module.evaluate();

console.log(module.namespace.x); // 42

This also includes support for createCachedData, produceCachedData, and cachedDataProduced properties, along with custom inspection for vm.Module.

Implemented thanks to @heimskr!

HTTPParser binding#

Bun v1.2.16 adds process.binding('http_parser') (also adding HTTPParser to node:_http_common), improving compatibility with Node.js HTTP internals.

index.js

const { HTTPParser } = process.binding('http_parser');

const parser = new HTTPParser();
parser.initialize(HTTPParser.REQUEST, {});

const input = Buffer.from("GET / HTTP/1.1\r\nHost: example.com\r\n\r\n");

parser[HTTPParser.kOnHeaders] = function () {
    console.log("Headers!");
};

parser.execute(input);

The implementation uses the llhttp library for parsing in order to match Node.js behavior exactly.

Thanks to @dylan-conway!

node:timers/promises accepts AbortController for options argument#

The functions in the node:timers/promises module accept an options argument which supports several properties, such as signal to provide an AbortSignal for cancelling the timer. Since AbortController objects also have a signal property, it should be possible to pass an AbortController directly in order to use its signal to cancel the timer:

import { setTimeout } from "node:timers/promises";

const controller = new AbortController();
const promise = setTimeout(100, undefined, controller);
controller.abort();

promise.catch((e) => console.error(e)); // AbortError

Previously, Bun's object validation was too strict and would reject the AbortController because it is not a plain object. Now this pattern is supported in Bun. This has fixed compatibility for certain Cloudflare Wrangler subcommands when run in Bun.

Thanks to @SunsetTechuila for this fix!

Memory leak fixes#

This release fixes a few memory leaks:

  • N-API handle scopes: Fixed rare race condition and memory leak in NapiHandleScopeImpl where garbage collection wasn't properly cleaning up handle scope implementations
  • Bun.spawn stdio: Fixed memory leak when piped stdio from Bun.spawn was never read.

Bugfixes#

Runtime bugfixes:

  • Fixed: bytesWritten calculation in node:net when handling buffered string writes
  • Fixed: process.stdin buffering issue on macOS where input wasn't being emitted incrementally
  • Fixed: potential exit signal hanging in loops
  • Fixed: duplicate Transfer-Encoding header sent in node:http in certain cases
  • Fixed: SharedArrayBuffer crashing on transfer
  • Fixed: crash when accessing cookies before proper initialization
  • Fixed: "undefined is not an object" error when interrupting Next.js dev server with Ctrl+C
  • Fixed: DevServer crash when using Tailwind CSS
  • Fixed: TOML parser incorrectly handling table array headers after inline tables

JavaScript parser bugfixes:

  • Fixed: crash with malformed function definitions

CSS parser bugfixes:

  • Fixed: CSS calc() expressions causing stack overflow with nested calculations
  • Fixed: radians incorrectly converted to degrees in CSS transform functions

FFI bugfixes:

  • Fixed: bun:ffi new CString() ignoring byteOffset argument when byteLength not provided

TLS bugfixes:

  • Fixed: TLS server identity verification improvements
  • Fixed: proper handling of IP range normalization (e.g., "8.8.8.0/24")

HTTP/2 bugfixes:

  • Fixed: HTTP/2 flow control and protocol handling issues

Windows bugfixes:

  • Fixed: crash handler now uses abort() instead of quick_exit(134) for better debugging
  • Fixed: WebKit and libpas dependencies updated for Windows builds

Environment variables:

  • Added: BUN_BE_BUN environment variable for running the Bun binary instead of the entry point of a single-file executable

CLI improvements:

  • Improved: help text formatting and documentation links for package manager commands
  • Removed: audit from bun pm help (use bun audit directly)

TypeScript types:

  • Fixed: RedisClient.prototype.del accepts one or more keys as arguments

Thanks to 25 contributors!#