AssemblyScript is a compiler that aims to compile TypeScript code (with slight differences to be able to make sense in Wasm, though trying to minimize those differences) into Wasm. To remain compatible with TypeScript (which is AssemblyScript's goal) and be an optimal language for Wasm that will communicate with TS/JS on the other side, the type `string` would need to be in the same format to avoid any perf hit or data loss while passing thing if that type across the Wasm-JS boundary.

I'm not sure what type of compiler to label that as, but that's the goal.