I think it's worded in a way that's odd to developers that usually write code for multiple target languages.
What you type is usually considered what it's implemented in, not what it's compiled/transpiled to. The later is the target language, which there may be many.
This differentiation is required if you want to modify/read the code. You would almost certainly modify/read it in the language it was implemented in, and make it clear which language this is when sharing.
Maybe "...implemented in TS, targeting JS" or at least something more obvious like "...implemented in JS using TS".
What you type is usually considered what it's implemented in, not what it's compiled/transpiled to. The later is the target language, which there may be many.
This differentiation is required if you want to modify/read the code. You would almost certainly modify/read it in the language it was implemented in, and make it clear which language this is when sharing.
Maybe "...implemented in TS, targeting JS" or at least something more obvious like "...implemented in JS using TS".