Bun creator Jarred Sumner noted that the runtime's ahead-of-time (AoT) compilation now allows TypeScript 6 to typecheck the Effect library slightly faster than TypeScript 7 in single-threaded tests. The tool is intended to be a 100% compatible replacement for `tsc` and part of a broader strategy to enable compiled JavaScript and TypeScript to match or exceed the performance of Go and other natively compiled languages.
Tuesday, October 20, 2026
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Bun Ships Built-in Rust Type Checker and Cuts Server CPU 67%
Tech11 days ago
JavaScript and TypeScript engineers now have access to a new internal verification tool designed to increase compilation efficiency. The utility, `bun check`, is part of the v1.4.3 update released Oct. 10 and is written in Rust to provide a fast, built-in alternative to the standard `tsc` tool. This version also reduces idle CPU usage in servers by 67%, resolves 166 issues, and introduces a `Bun.FetchSession` API along with faster `JSON.parse` functionality.
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