My language was perhaps not as clear as it could be, given that we're talking about compiling compilers. This is about the native code of the compiler itself. The original Typescript compiler ran as regular JS inside a JS engine. The Go rewrite compiles the Typescript compiler to native code. This rewrite also compiles the Typescripter compiler to native code. In both cases, the Typescript compiler is now running directly on the OS rather than inside a JS engine, so both are significantly faster at compiling Typescript programs. However, the natively-running Typescript compiler compiled by Go still has a garbage collector itself. You don't need a garbage collector running while translating Typescript code to Javascript.