Bun: A Complete Overhaul of the JavaScript Ecosystem
&gt; I&#x27;m not sure if Bun is also a complete rewrite of the TypeScript compiler, but it appears to be.<p>I thought it used ESBuild for that part.<p>Looking in Bun&#x27;s Git repo, I see under Credits:<p>&gt; While written in Zig instead of Go, bun’s JS transpiler, CSS lexer, and node module resolver source code is based on @evanw’s esbuild project.<p><a href="https:&#x2F;&#x2F;github.com&#x2F;oven-sh&#x2F;bun#credits" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;oven-sh&#x2F;bun#credits</a><p>Reading it this time, I understand ESBuild was only used as a reference, and Bun&#x27;s transpiler is indeed a fresh rewrite.<p>Same as ESBuild, it does no typechecking.<p>&gt; Bun doesn&#x27;t actually typecheck the TypeScript code. It only transpiles it to javascript. Typechecking should be handled either by your IDE or other tools like tsc.