---
title: Bun v1.1.37
description: "Fixes 62 bugs (addressing 109 👍). Realtime error reporting & test runner in VSCode, self-referencing `import` & `require`, package.json `config` environment variables, improved CSS parser errors, fixes for a Prisma memory leak, a `bun install` regression, `expect.toMatchSnapshot` quote escaping, `node:net` regression impacting `http2-wrapper`, and several other bugfixes and improvements."
date: "2024-11-26T00:58:38.736Z"
author: dylan
---

{% callout %}
We're hiring [systems engineers](/careers) in San Francisco to build the future of JavaScript!
{% /callout %}

This release fixes 62 bugs (addressing 109 👍). It introduces realtime error reporting & test runner in VSCode, self-referencing `import` & `require`, package.json `config` environment variables, improved CSS parser errors, fixes for a Prisma memory leak, a `bun install` regression, `expect.toMatchSnapshot` quote escaping, `node:net` regression impacting `http2-wrapper`, and several other bugfixes and improvements.

#### To install Bun

{% codetabs %}

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

```sh#npm
$ npm install -g bun
```

```sh#powershell
$ powershell -c "irm bun.sh/install.ps1|iex"
```

```sh#scoop
$ scoop install bun
```

```sh#brew
$ brew tap oven-sh/bun
$ brew install bun
```

```sh#docker
$ docker pull oven/bun
$ docker run --rm --init --ulimit memlock=-1:-1 oven/bun
```

{% /codetabs %}

#### To upgrade Bun

```sh
$ bun upgrade
```

## Realtime debuggerless error reporting in VSCode

[Bun for VSCode](https://marketplace.visualstudio.com/items?itemName=oven-sh.bun) now reports runtime errors with their stack trace in the "Problems" tab when you run bun in the VSCode terminal. This works without the debugger attached, with no configuration, and no need to pause execution. There's nothing extra to configure, it just works.

To get started:

1. Install [Bun for VSCode](https://marketplace.visualstudio.com/items?itemName=oven-sh.bun)
2. Open a terminal in VSCode
3. Run `bun test --watch`, `bun run foo.ts`, or any other script
4. Watch errors reported in the "Problems" tab

{% image src="https://raw.githubusercontent.com/oven-sh/bun/d7a050dd4bdea443c979f0bd1061024e1cc669ba/packages/bun-vscode/error-messages.gif" /%}

{% raw %}

<!--
<blockquote class="twitter-tweet"><p lang="en" dir="ltr">In the next version of Bun<br><br>Bun&#39;s VSCode extension reports runtime errors in your editor exactly where they happen <a href="https://t.co/9QsJmZoSuP">pic.twitter.com/9QsJmZoSuP</a></p>&mdash; alistair (@alistaiir) <a href="https://twitter.com/alistaiir/status/1859065164303396952?ref_src=twsrc%5Etfw">November 20, 2024</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script> -->

{% /raw %}

### How is this different from tools like TypeScript, ESLint, and Biome?

Runtime errors have no false positives, but they only appear when you run the code.

Runtime errors only appear when the error prevents further execution, such as an uncaught exception, a rejected promise, or a test failure that halted execution. You'll usually only get 1 error in total, unlike static analysis tools that report many errors without running any code.

#### Can I still use TypeScript, ESLint, or Biome?

**Yes!** This works perfectly alongside static analysis tools like TypeScript, ESLint, or Biome. It doesn't compete or replace them.

This reports errors that static analysis tools can't catch:

- Filesystem errors like `ENOENT`
- Syntax errors from parsing invalid JSON
- Exceptions like `TypeError` and `RangeError`

On the other hand, this will only report one error at a time. It doesn't come from reading your code, it comes from running your code.

Big thanks to [@alii](https://github.com/alii) for implementing this.

### Self-referencing `import` & `require`

Bun v1.1.37 adds support for self-referencing imports within a module. This allows modules to import themselves by name through the `exports` field in their package.json.

Given the package.json and foo.js for module `foo`:

{% codetabs %}

```json#./package.json
{
    "name": "foo",
    "exports": {
        ".": "./foo.js"
    }
}
```

```js#./foo.js
import * as foo from 'foo';
export const bar = foo;
```

{% /codetabs %}

The following code in `index.js` will print `true`:

```js#./index.js
import * as foo from 'foo';
console.log(foo.bar === foo); // true
```

Implemented thanks to [@SunsetTechuila](https://github.com/SunsetTechuila)!

### Memory leak impacting Prisma fixed

`napi_threadsafe_function` is a structure that can be used by other threads to enqueue requests to call a function on the main JavaScript thread. This is necessary since JavaScript is single-threaded, and you can't access the JavaScript engine from any other thread. Previous versions of Bun never freed the queue used to keep track of pending calls to the threadsafe function, which manifested as an 8-byte memory leak for each Prisma query since every query creates a threadsafe function with a queue size of 1. We expect this change may fix memory leaks in other Node-API packages too, but Prisma was the most widely-reported leak.

{% raw %}

<blockquote class="twitter-tweet"><p lang="en" dir="ltr">In the next version of Bun<br><br>A slow memory leak impacting napi &amp; Prisma has been fixed <a href="https://t.co/Dl1ZeXEFmj">pic.twitter.com/Dl1ZeXEFmj</a></p>&mdash; Bun (@bunjavascript) <a href="https://twitter.com/bunjavascript/status/1859323013700911223?ref_src=twsrc%5Etfw">November 20, 2024</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>

{% /raw %}

### Crash in `shadcn` & `sv` on Windows fixed

A crash on Windows, commonly seen in cli packages like `shadcn`, `sv`, `prompts`, `solidui-cli`, and `create-astro`, has been fixed. The bug existed in `node:readline` `setRawMode` in C++ where a type was incorrectly casted to another.

Fixed thanks to [@heimskr](https://github.com/heimskr)!

### `npm_package_config_` environment variables using `bun run`

We've added support for populating `npm_package_config_` environment variables from the `config` field in package.json.

Given the package.json:

```json#package.json
{
    "name": "env",
    "config": {
        "foo": "bar",
    },
    "scripts": {
        "echo": "echo $npm_package_config_foo"
    }
}
```

Running `bun run echo` will print `bar`.

We've also added `npm_lifecycle_event` for script names, `npm_lifecycle_script` for script values, and `npm_command` variables for `bun run`, `bun publish`, and `bun pm pack`.

```
bun run:      npm_command=run-script
bun publish:  npm_command=publish
bun pm pack:  npm_command=pack
```

Thanks to [@nektro](https://github.com/nektro)!

### Improved CSS parser error messages

We've changed the error messages in our CSS parser to be more descriptive and helpful. For example, declaring a rule before `@import` produces:

{% codetabs %}

```sh
$ bun build --experimental-css red.css

error: @import rules must come before any other rules except @charset and @layer
    at /path/to/red.css:5:8
```

```css#red.css
div {
    color: red;
}

@import url('blue.css');
```

{% /codetabs %}

This and many other errors have been improved in this release. A snippet of the changes:

```diff#src/css/error.zig
return switch (this) {
-    .at_rule_invalid => |name| writer.print("at_rule_invalid: {s}", .{name}),
-    .unexpected_token => |token| writer.print("unexpected_token: {}", .{token}),
-    .selector_error => |err| writer.print("selector_error: {}", .{err}),
-    else => writer.print("{s}", .{@tagName(this)}),
+    .at_rule_body_invalid => writer.writeAll("Invalid at-rule body"),
+    .at_rule_prelude_invalid => writer.writeAll("Invalid at-rule prelude"),
+    .at_rule_invalid => |name| writer.print("Unknown at-rule @{s}", .{name}),
+    .end_of_input => writer.writeAll("Unexpected end of input"),
+    .invalid_declaration => writer.writeAll("Invalid declaration"),
+    .invalid_media_query => writer.writeAll("Invalid media query"),
+    .invalid_nesting => writer.writeAll("Invalid CSS nesting"),
+    .deprecated_nest_rule => writer.writeAll("The @nest rule is deprecated, use standard CSS nesting instead"),
+    .invalid_page_selector => writer.writeAll("Invalid @page selector"),
+    .invalid_value => writer.writeAll("Invalid value"),
+    .qualified_rule_invalid => writer.writeAll("Invalid qualified rule"),
+    .selector_error => |err| writer.print("Invalid selector. {s}", .{err}),
+    .unexpected_import_rule => writer.writeAll("@import rules must come before any other rules except @charset and @layer"),
+    .unexpected_namespace_rule => writer.writeAll("@namespace rules must come before any other rules except @charset, @import, and @layer"),
+    .unexpected_token => |token| writer.print("Unexpected token. {}", .{token}),
+    .maximum_nesting_depth => writer.writeAll("Maximum CSS nesting depth exceeded"),
};
```

Thanks to [@zackradisic](https://github.com/zackradisic)!

### Improved `Bun.write` error messages

`Bun.write` now prints the received value when passed an unexpected argument. For example, passing a BigInt as the first argument will print:

```sh
$ bun --print "Bun.write(1n, 'hello stdout')"

TypeError: The "destination" argument must be of type path, file descriptor, or Blob. Received 1n
 code: "ERR_INVALID_ARG_TYPE"

      at /home/[eval]:1:5

Bun v1.1.37 (macOS arm64)
```

Thanks to [@nektro](https://github.com/nektro)!

### `performance.markResourceTiming` stub

We've stubbed `performance.markResourceTiming` to unblock packages that rely on it. While the function will only return `undefined`, it will no longer throw runtime errors in packages like `@sveltejs/adapter-cloudflare`.

### `Bun.file` throws OOM errors if the file is too large on Windows

Given a file larger than 4GB, `Bun.file` will now throw an OOM error on Windows. Previously, it would crash with an assertion failure. Fixed thanks to [@cirospaciari](https://github.com/cirospaciari)!

```js#index.js
const hugeFile = Bun.file('huge-file.txt'); // throws ENOMEM
console.log(hugeFile.size);
```

### Fixed regression in `bun install`

Part of the work towards reducing the binary size of Bun in v1.1.35 was moving Bun's package manager state out of the BSS section of the binary, and heap allocating it when needed. This change caused crashes when parsing aliased dependencies (e.g. `npm:zod@1.11.17`) due to accessing undefined memory.

This has been fixed in this release, thanks to [@dylan-conway](https://github.com/dylan-conway)!

### Fixed quote and template escaping in `expect.toMatchSnapshot`

`expect.toMatchSnapshot` writes the stringified test name plus a counter and the received value to disk, both within a template literal. The release fixing escaping issues where backticks and ${} were not escaped correcly, causing snapshot to fail to match upon re-running the test.

```ts#index.test.ts
import { expect, test } from "bun:test";

test("snapshot `foo`", () => {
    const foo: string = "hello ${}!";
    expect(bar).toMatchSnapshot();
});
```

Fixed thanks to [@pfgithub](https://github.com/pfgithub)!

### Fixed `bun --hot` with single quote in the entrypoint

Previously `bun --hot` would report a syntax error when the entrypoint contained a single quote.

```sh
$ bun --hot "src/single'quote.ts"
```

Now, Bun will run the entrypoint as expected, thanks to [@pfgithub](https://github.com/pfgithub)!

### Fixed `WebSocket.ping` called without arguments

A bug was fixed where calling `WebSocket.ping` without arguments would fail to send a message without a payload.

```js
import { WebSocketServer } from "ws";

const server = new WebSocketServer({ noServer: true });

server.on("connection", (ws) => {
  ws.ping(); // fixed
});
```

Fixed thanks to [@cirospaciari](https://github.com/cirospaciari)!

### Regression in printing `\uFFFF`

A regression in our JavaScript printer caused `\uFFFF` to print incorrectly. This has been fixed and now works as expected.

```sh
$ bun --print "'\uFFFF'.charCodeAt(1)"
# Previously:  57343
# Bun v1.1.37: NaN
```

Thanks to [@pfgithub](https://github.com/pfgithub)!

### Non-zero for non-existent absolute file path in `bun test`

Given an aboslute file path to a file that does not exist, `bun test` will now exit with a non-zero exit code along with a module resolution error. Previously, the error would be reported but the exit code would be 0.

```sh
$ bun test /path/to/non-existent-file.test.ts

error: ModuleNotFound resolving "/path/to/non-existent-file.test.ts" (entry point)
```

### `node:net` regression fixed

A regression impacting the `http2-wrapper` package has been fixed. The cause was a change in the `node:net` builtin module, where `TLSSocket._handle._parentWrap` was not set to `JSStreamSocket` correctly.

### Fixed errors printing twice in watch or hot mode

Running a script with `--watch` or `--hot` would print unhandled exceptions to the console twice. A simple example of this would be:

```js-diff
  $ bun --watch --print "throw new Error('oops!')"
  1 | throw new Error('oops')
            ^
  error: oops!
        at /home/user/[eval]:1:7
- 1 | throw new Error('oops')
-           ^
- error: oops!
-       at /home/user/[eval]:1:7
```

This has been fixed and now only prints once, thanks to [@alii](https://github.com/alii)!

### Targeting browser with `node:buffer` in `bun build`

A bug preventing `Buffer` imports from `node:buffer` when targeting the browser with `bun build` has been fixed. Existing code could access `Buffer` through the default export, but importing `Buffer` directly would fail.

```js
import { Buffer } from "node:buffer";
const buf = Buffer.from("bun!");
console.log(buf.toString());
```

```sh
$ bun build --target browser --outfile out.js
# Previously:  error: No matching export in "../../../../../bun-vfs$$/node_modules/buffer/index.js" for import "Buffer"
# Bun v1.1.37: out.js  41.66 KB
```

## Thanks to 14 contributors!

- [@advaith1](https://github.com/advaith1)
- [@alii](https://github.com/alii)
- [@cirospaciari](https://github.com/cirospaciari)
- [@Electroid](https://github.com/Electroid)
- [@heimskr](https://github.com/heimskr)
- [@imide](https://github.com/imide)
- [@Jarred-Sumner](https://github.com/Jarred-Sumner)
- [@luavixen](https://github.com/luavixen)
- [@Nanome203](https://github.com/Nanome203)
- [@nektro](https://github.com/nektro)
- [@pfgithub](https://github.com/pfgithub)
- [@RiskyMH](https://github.com/RiskyMH)
- [@rtzll](https://github.com/rtzll)
- [@SunsetTechuila](https://github.com/SunsetTechuila)