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Watch TypeScript creator Anders Hejlsberg on The Peterman Pod
Watch TypeScript creator Anders Hejlsberg on The Peterman Pod
Following the release of TypeScript 7.0, Hejlsberg joins host Ryan Peterman to discuss the process of porting from JavaScript to Go, the pros and cons of agentic AI for coding, and more.
By Command Line teamCommand Line editorial team
2026.08.17
How does a team tackle the port of one of the most popular coding languages used every day by millions of developers?
In 2025, TypeScript was the most used language on GitHub, according to the 2025 GitHub Octoverse report. And in July 2026, the TypeScript team released TypeScript 7.0. The new TypeScript is a 10x faster native port designed to streamline the developer experience, with core editor features like auto-completion and diagnostics now taking a fraction of the time they used to. The creator of TypeScript and Microsoft Technical Fellow Anders Hejlsberg recently sat down with host Ryan Peterman to record an episode of The Peterman Pod. They discussed the process of porting from TypeScript to Go, the technical decisions and tradeoffs the team made, and lessons learned along the way. They also talked about Hejlsberg’s approach to creating programming languages, the use of AI to update large codebases, and both the value and limitations of agentic AI today.
Check out the full episode:
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From the beginning, TypeScript promised to deliver JavaScript that scales. By incorporating strong type-checking and rich tooling, TypeScript made it possible to build and ship non-trivial, high-quality apps across platforms.
“We all stand on the shoulders of giants,” acknowledged Hejlsberg. “No programming language was ever created in perfect isolation, right? Everyone learns from everyone. Someone comes up with a good idea, and then you see it adopted elsewhere. That’s how the industry moves forward, really.”
“No programming language was ever created in perfect isolation.”
– Anders Hejlsberg
The TypeScript team worked for more than a year on a native port built in Go that could make the most of modern hardware. The port maintained the structure and logic of the original codebase to keep results consistent and compatible between the two compilers. The key difference: TypeScript 7 brings native code speed, shared memory multithreading, and several new optimizations that typically yield increased speeds of between 8x and 12x on full builds.
“The first decision we made was that we were not going to rewrite,” Hejlsberg said. “We were going to port because only by porting could we preserve the semantics, algorithms, and exact behavior of our existing compiler, which everyone depends on for backwards compatibility. Now, we could have cleaned the slate and started it completely from scratch, but we would have come up with a different language in the sense that it would give you different errors or behave differently in certain situations.”
Next, the team had to decide on a programming language for the port. After looking at some core assumptions made by the TypeScript codebase—the presence of garbage collection as well as the first-class treatment of functions, for example—Go emerged as the clear winner.
“We tried Rust, and it just wasn’t feasible.”
– Anders Hejlsberg
“We tried Rust, and it just wasn’t feasible,” noted Hejlsberg. “Garbage collection is done manually, or it’s done through the borrow checker, but the borrow checker doesn’t allow circular data structures. And our complier is chock-full of circular data structures. We have trees with parent pointers; we have types that are recursive. I mean, it’s everywhere. We were trying to optimize for doing as little work as possible to get us to...