Bun 1.4 updates the JavaScript and TypeScript runtime, package manager, test runner, and bundler with a Rust rewrite, expanded Node.js compatibility, lower resource use, and new built-in APIs. The release adds 1,517 Node.js test-suite tests and fixes more than 2,900 issues. Bun reports that node:http, fs, cluster, timers, zlib, vm, and stream now pass 97% of Node’s own tests, while node:quic passes 99% and node:events, trace_events, and sqlite pass 100%. Bun says idle CPU use falls fivefold for a small application, HTTP-server memory use declines by 13% to 48%, and Linux startup time for a hello-world script drops from 10.9 ms in Bun 1.3 to 5.1 ms. New native Web Streams, CompressionStream and DecompressionStream implementations, and improved response cloning reduce memory use and improve streaming throughput. New built-ins include Bun.Image for image conversion and resizing, Bun.WebView for browser automation, Bun.markdown, Bun.cron(), and Bun.Terminal. Package-management additions include bun audit fix, bun dedupe, bun prune, package diffs, license reporting, and transitive dependency updates. Bun 1.4 also adds parallel script and test execution, test sharding and timing-based balancing, built-in React Compiler support, directory serving in Bun.serve(), and experimental HTTP/2 and HTTP/3 capabilities.

Deno 2.9 introduces Deno Desktop, allowing the creation of native desktop applications using familiar web technologies without Electron. The release simplifies migration from Node.js by enabling deno install to read npm, pnpm, yarn, and Bun lockfiles directly.

Edge.js is an open-source JavaScript runtime that enables the safe execution of Node.js workloads within a WebAssembly sandbox. It aims to achieve improved density and faster startup times compared to traditional containerized environments.