Deno supports TypeScript out of the box, but still effectively uses the transpiler under the hood. TypeScript is designed for the JavaScript runtime, with the

Deno supports TypeScript out of the box, but still effectively uses the transpiler under the hood. TypeScript is designed for the JavaScript runtime, with the only difference being additional compile-time type checks. The runtime behaviour is basically defined as the JS runtime behaviour, so any alternative engine will have to be a full JavaScript engine. That said, there are some projects that take a subset of TypeScript and run using different implementations. One example is https://github.com/AssemblyScript/assemblyscript https://github.com/AssemblyScript/assemblyscript However, being a subset, the available functionality will be a lot more limited.