Download Bun 1.3.13

Fixes 82 issues (addressing 381 👍). bun test --parallel, --isolate, --shard, and --changed, bun install streams tarballs to disk using 17x less memory, source maps use 8x less memory, 5.5x faster gzip with zlib-ng, Range request support in Bun.serve(), SHA3 in node:crypto and WebCrypto, ws+unix:// WebSocket client, and many bugfixes and Node.js compatibility improvements

Features
- bun test --isolate runs each test file in a fresh global environment within the same process, draining microtasks, closing sockets, cancelling timers, killing subprocesses, and creating a clean global object between files.
- bun test --parallel[=N] distributes test files across up to N worker processes (default CPU count), partitioning for cache locality and stealing work from idle workers; output remains identical to serial execution.
- bun test --shard=M/N splits test files across CI jobs, sorting by path and distributing round‑robin; works with --changed and --randomize, exits gracefully when a shard has no files.
- bun test --changed runs only test files affected by git changes, building an import graph and filtering to transitive dependents; supports --watch for re‑filtering on every restart.
- bun install streams tarballs to disk: extracts package tarballs while downloading, using only in‑flight HTTP chunks plus fixed buffers, reducing memory usage by ~17x.
- Faster bun install with isolated linker: `bun install --linker=isolated` speeds up installs in peer‑heavy monorepos.
- Source maps use up to 8x less memory: compact bit‑packed binary format (~2.4 B per mapping) replaces full VLQ list, reducing resident size from ~11 MB to ~1.3 MB for large projects.
- Bun’s runtime uses 5% less memory: upgraded mimalloc to v3 and added libpas scavenger support for Windows and Linux, improving baseline usage and reducing hangs/crashes.
- Upgraded JavaScriptCore engine (1,316 upstream commits) with performance improvements such as inline cache for array length, property keys, string length folding, toUpperCase intrinsic, fast path for String#indexOf, redundant mov removal, cached date formatters, wider bulk copy in GC‑safe memcpy, SIMD‑accelerated case‑insensitive comparisons, and SIMD fast path for identifier parsing.
- Faster addEventListener, dispatchEvent, and DOM events via ~270 upstream WebKit commits.
- File streaming improvements in Bun.serve(): Response(Bun.file(path)) now streams incrementally on SSL and Windows, reducing memory usage for large files.
- Range request support in Bun.serve(): automatic handling of `Range` headers for static and dynamic file responses, returning 206 Partial Content or 416 as appropriate.
- Up to 5.5x faster gzip compression with zlib‑ng 2.3.3: SIMD‑accelerated CRC32, Adler32, longest‑match and chunk‑copy operations; benchmarks show 2.5‑5.5× speedups for gzip/deflate.
- Faster array iteration in Bun’s internals: up to 1.43× speedup for common cases by reading elements directly from JSC’s butterfly memory.
- SHA3 support in WebCrypto and node:crypto: SHA3‑224/256/384/512 available via `crypto.createHash`, `crypto.createHmac`, `crypto.subtle.digest`, etc.
- X25519 deriveBits support in SubtleCrypto: full X25519 key agreement implementation, handling small‑order public keys per RFC 7748.
- WebSocket client now supports `ws+unix://` and `wss+unix://` URLs for Unix domain socket connections, with proper Host header and proxy handling.
- Standalone HTML built with `bun build --compile --target browser` now inlines file‑loader assets imported from JavaScript as data URIs.
- `bunx claude` is now an alias for `bunx @anthropic-ai/claude-code`.

Bugfixes
- Node.js compatibility improvements: fixed worker lifecycle crashes, tls.connect host handling, passphrase option crashes, process.ppid caching, --cpu-prof output format, socket.setTimeout spurious timeouts, node:http2.createServer ENABLE_PUSH issue, StringDecoder.write crash, native N‑API module finalizer order, dgram source‑specific membership options, os.freemem on Linux, rare fs.watch deadlock, path.win32.resolve crash, fs.writeSync crash on Windows, root certificate race condition, macOS syscalls EINTR handling, re‑export with string‑literal names, Error.captureStackTrace with non‑numeric stackTraceLimit, preventDefault on non‑passive listeners, WebIDL integer conversion rounding, BroadcastChannel data races.
- Bun APIs fixes: Bun.inspect and console.log class name display, server.stop hanging, file descriptor leaks in static routes, error handler file‑backed Response drop, duplicate Content‑Length headers, MySQL adapter hanging on multi‑statement queries, Bun.YAML.parse crash, sliced non‑regular file blob crash, large file size fstat panic and OOM handling, Bun.RedisClient crash on GC after argument validation error, Bun.pathToFileURL Windows crash, MKADDRESSBOOK CardDAV method handling, AbortSignal memory leak in WebSocket upgrade, ~1 KB memory leak per hot reload, memory leak in Glob.scan.
- Web APIs fixes: controller.abort on queued fetch now rejects immediately, AbortSignal.timeout leak, fetch hanging with tls.checkServerIdentity, fetch abort crash, fetch HTTP_PROXY port injection bug, ws.close crash behind CONNECT proxy, WebSocket client send buffer leak, promise resolution crash, record conversion crash with numeric‑index keys and shared ArrayBuffer.
- bun install: fixed bunx @anthropic‑ai/claude‑code executable detection.
- JavaScript bundler fixes: broken binaries on macOS ARM64 (v1.3.12), HTML import etag not updating, broken executables on NixOS/Guix, resolver race crash with failing sibling import, auto‑install invalid npm package names crash.
- CSS Parser fix: preserved top‑level @layer ordering declarations.
- bun test fix: toMatchSnapshot counter reset with --rerun-each, retry, repeats.
- Windows fixes: runtime transpiler race condition crash, NaN/inf timer crash, readFile >2 GB crash, fs.readdir malformed entry crash, libpas resource exhaustion, pthread_once and mprotect issues.
- JavaScript engine fixes: RegExp exec/test ToLength issue, namespace import handling, TypedArray iterator with detached buffers, Date.toLocaleString crash in Worker, YARR backtracking bugs, class field eval context propagation, DFG constant folding and BitAnd bugs.
- Internal / Runtime fixes: debugger pause CPU usage, macOS arm64 deadlock between allocator and thread pool, 8 libpas memory‑accounting bugs, early‑exit state partial initialization bugs (HTTP decompression, Request/Response bodies, Bun.build plugin errors, named pipe listeners), socket layer context pointer dereference after unlink, event loop timer sweep iterator crash.