--- title: Bun v1.2.7 description: "Fixes 35 bugs (addressing 219 👍). Bun.CookieMap is a Map-like API for getting & setting cookies. Bun's TypeScript type declarations have been rewritten to eliminate conflicts with Node.js and DOM type definitions. Several bugfixes for node:http, node:crypto, and node:vm." date: "2025-03-27T08:51:16.122Z" author: jarred --- This release fixes 35 bugs (addressing 219 👍). Bun.CookieMap is a Map-like API for getting & setting cookies. Bun's TypeScript type declarations have been rewritten to eliminate conflicts with Node.js and DOM type definitions. Several bugfixes for node:http, node:crypto, and node:vm. #### 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 ``` ## Bun.Cookie & Bun.CookieMap Most production web applications read and write cookies. Today in server-side JavaScript, you must choose either a single-purpose cookie parsing library like `tough-cookie`, or adopting a web framework like Express or Elysia. Cookie parsing & serialization is a well-understood problem. We can simplify this by moving it up the stack from the framework or library to the web server in Bun. Bun's HTTP server now has built-in support for reading and writing cookies using a Map-like API. `request.cookies` detects changes and automatically adds the `Set-Cookie` header to the `Response` when needed. This is one less library to shop for when building web applications with Bun. ```ts import { randomUUIDv7, serve, CookieMap } from "bun"; const server = Bun.serve({ routes: { "/api/users/sign-in": (request) => { const cookies: CookieMap = request.cookies; const sessionId = randomUUIDv7(); cookies.set("sessionId", sessionId, { httpOnly: true, sameSite: "strict", }); // Modifying cookies tells Bun.serve() to automatically // add the Set-Cookie header to the response return new Response("Signed in"); }, "/api/users/sign-out": (request) => { // .delete makes the Set-Cookie header expire & set the cookie to an empty value request.cookies.delete("sessionId"); return new Response("Signed out"); }, }, }); ``` For performance reasons, the `Cookie` header is not parsed until you access the `request.cookies` property. So you don't pay the cost of this feature unless you need it. When you modify a cookie, Bun.serve() automatically adds the `Set-Cookie` header to the Response, so that you don't have to worry about conditionally remembering to add the exact number of `Set-Cookie` headers necessary to correctly decide & modify which cookies to send to the client. ### Cookies outside of Bun.serve() You can also read and write cookies outside of Bun.serve() using the `Bun.Cookie` and `Bun.CookieMap` classes. ```ts const cookie = new Bun.Cookie("sessionId", "123"); cookie.value = "456"; console.log(cookie.value); // "456" console.log(cookie.serialize()); // "sessionId=456; Path=/; SameSite=lax" const cookieMap = new Bun.CookieMap(); cookieMap.set("user1", "hello"); console.log(cookieMap.get("user1")); // "hello" cookieMap.set("user2", "world"); console.log(cookieMap.toSetCookieHeaders()); // => [ "user1=hello; Path=/; SameSite=Lax", "user2=world; Path=/; SameSite=Lax" ] ``` Thanks to [@pfgithub](https://github.com/pfgithub)! ## TypeScript type improvements Bun's TypeScript declarations have been completely rewritten to eliminate conflicts with Node.js and DOM type definitions, providing a better developer experience with fewer type errors. ```ts#index.ts Buffer.from("foo").equals(Buffer.from("bar")) ``` Previously, in certain setups this could fail to type check with: ```bash Argument of type 'Buffer' is not assignable to parameter of type 'Uint8Array'. The types returned by 'entries()' are incompatible between these types. Type 'IterableIterator<[number, number]>' is missing the following properties from type 'ArrayIterator<[number, number]>': map, filter, take, drop, and 9 more.ts(2345) ``` This update fixes numerous type-related issues, improves documentation generation, and refines the overall TypeScript experience in Bun. Thanks to [@alii](https://github.com/alii) for the contribution! ## Fixed: `node:http` regression from v1.2.6 Fixed a regression from v1.2.6 where `node:http` could crash in certain cases. Fixed thanks to [@heimskr](https://github.com/heimskr)! ## Fixed: `node:crypto` Hash Name Regression Fixed a regression in `node:crypto` module where hash names in `crypto.getHashes()` and `crypto.getCiphers()` were incorrectly returned in uppercase instead of the expected lowercase format. This ensures compatibility with Node.js behavior and proper hash name detection. ```js // Before (incorrect) crypto.getHashes(); // Returns ["MD5", "SHA1", "SHA256", ...] // After (fixed) crypto.getHashes(); // Returns ["md5", "sha1", "sha256", ...] ``` Thanks to [@dylan-conway](https://github.com/dylan-conway) for the contribution! ## Fixed: `node:http` set-cookie handling Bun v1.2.7 enhances Node.js compatibility in the HTTP module with better cookie handling. The update improves how Set-Cookie headers are processed and adds validation for HTTP options. ```js // Set multiple cookies using array format const server = http.createServer((req, res) => { res.writeHead(200, [ ["set-cookie", "SessionID=123"], ["set-cookie", "Preferences=dark-mode"], ["content-type", "application/json"], ]); res.end(JSON.stringify({ success: true })); ``` Thanks to [@cirospaciari](https://github.com/cirospaciari) for the contribution! ## Fixed: `node:vm` options object bug A bug in `node:vm` where `undefined` in options could cause it to throw an error instead of treating as a default value has been fixed. ```js // This now works correctly const vm = require("node:vm"); vm.runInNewContext( "console.log('hello')", {}, { timeout: undefined, cachedData: undefined, produceCachedData: undefined, }, ); ``` Thanks to [@SunsetTechuila](https://github.com/SunsetTechuila) for the contribution! ## Improved: error message when using libuv functions on unsupported platforms Bun now provides better error messages when a NAPI module attempts to access libuv functions that aren't supported. Previously, these attempts would result in cryptic crash messages like `dyld[1795]: missing symbol called`. Now, Bun provides clear, descriptive error messages that help identify the unsupported libuv function. ```diff - dyld[1795]: missing symbol called - zsh: abort bun index.js + Bun encounter a crash when running a NAPI module that tried to call + the uv_hrtime libuv function. ``` Thanks to [@zackradisic](https://github.com/zackradisic) for the contribution! ### Thanks to 13 contributors! - [@190n](https://github.com/190n) - [@alii](https://github.com/alii) - [@cirospaciari](https://github.com/cirospaciari) - [@donisaac](https://github.com/donisaac) - [@dylan-conway](https://github.com/dylan-conway) - [@gwer](https://github.com/gwer) - [@heimskr](https://github.com/heimskr) - [@jarred-sumner](https://github.com/jarred-sumner) - [@nanome203](https://github.com/nanome203) - [@pfgithub](https://github.com/pfgithub) - [@sunsettechuila](https://github.com/sunsettechuila) - [@twlite](https://github.com/twlite) - [@zackradisic](https://github.com/zackradisic)