Before that, I&#x27;d ask if the implementation of OCaml&#x27;s map is at all similar to the implementation of Immutable.js&#x27;s Map. Different internal data structures&#x2F;algorithms are probably the most likely explanation for any difference. Still, it&#x27;s nice to see a benchmark that shows how OCaml compiled to JS is competitive in performance, even when compared to a very popular library that is known for performing well.