Bun v1.3.9 introduces parallel and sequential script execution with `--parallel` and `--sequential` flags, supporting workspace filtering and Foreman-style output. Testing improvements include `Symbol.dispose` support for automatic mock cleanup. Performance enhancements include SIMD-accelerated RegExp matching, faster string operations (trim, startsWith), optimized Markdown rendering, and ESM bytecode compilation support. HTTP/2 connection upgrades via net.Server now work correctly. Bug fixes address ARM64 crashes, Windows filesystem operations, WebSocket stability, and HTTP proxy keep-alive issues.
Table of contents
bun run --parallel and bun run --sequentialHTTP/2 Connection Upgrades via net.ServerSymbol.dispose support for mock() and spyOn()NO_PROXY now respected for explicit proxy options--cpu-prof-interval flagESM bytecode in --compileFixed: Illegal instruction (SIGILL) crashes on ARMv8.0 aarch64 CPUsFaster Markdown-to-HTML renderingFaster Bun.markdown.react()Faster AbortSignal.abort() with no listenersJavaScriptCore upgradeBugfixesSort: