devtools.fm: Developer Tools, Open Source, Software Development Oliver Medhurst - Porffor - JavaScript Ahead of Time Compiler
Oct 20, 2025
Oliver Medhurst, the creator of Porffor, an ahead-of-time JavaScript-to-WebAssembly compiler, shares his fascinating journey from hobbyist to Mozilla contributor. He discusses the advantages of ahead-of-time compilation, tackling dynamic features, and the skepticism surrounding it. Oliver explains Porffor's TypeScript integration, benefits for serverless architecture, and how it addresses performance issues. He also touches on security benefits of WebAssembly and the future of JavaScript engines, highlighting ongoing optimizations and the evolving developer ecosystem.
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AOT Removes Cold Starts
- Ahead-of-time compiling trades runtime flexibility for zero startup and warm-up time, making JS behave like a native binary.
- Oliver shows this yields massive cold-start wins for server and edge use cases versus JITs.
Closures Are Harder Than They Look
- Closures are deceptively difficult to implement efficiently in an AOT JS compiler.
- Oliver found naive approaches either break semantics or cause heavy memory and performance penalties.
Leverage Optional Types For Faster Code
- Use optional TypeScript annotations as compiler hints to produce faster, safer compiled code.
- Oliver recommends opt-in types so the compiler can assume stable types and skip runtime checks.