This looks suspiciously similar to what LTeX produces for me. Are you sure that this is not the true origin of the error? If this is indeed LTeX, you will see it in :LspInfo
.
If so, here is some info about changing the language of LTeX: https://valentjn.github.io/ltex/advanced-usage.html In short, you could try \usepackage[french]{babel}
, or LTeX: language=fr-FR
.
Same in Python, Rust, Haskell and probably many others.
But apparently JS does work that way, that is its
filter
always iterates over everything and returns a new array and not some iterator object.