Clojurians Log v2

I found this error while interop-ing with scittle, I did found some workarounds, but why is this?

<script>
    var a_value = "hello a_value"
    var another = { value: "hello_another_value"}
</script>
<script type="application/x-scittle">
    (println js/a_value)
    (println js/another.value)
    ;; (set! js/a_value "goodbye a_value") ;; this is an error "Invalid assignment target"
    ;; (set! js/another.value "goodbye another_value") ;; this is also the same error
    (set! (. js/window -a_value) "goodbye a_value")
    (println js/a_value)
    (set! (.. js/another -value) "goodbye another_value")
    (println js/another.value)
    (set! (.-value js/another) "goodbye another_value 2")
    (println js/another.value)
</script>

@kyogatama officially you have to write (set! (.-a_value js/document) ...)

$ nbb
Welcome to nbb v1.2.173!
user=> (set! (.-a_value js/globalThis) 3)
nil
user=> js/globalThis.a_value
3