# Unimplemented Javascript primitive caml\_pure\_js\_expr

**URL:** <https://discuss.ocaml.org/t/unimplemented-javascript-primitive-caml-pure-js-expr/3248>\
**Category:** Community\
**Tags:** js\_of\_ocaml\
**Created:** [January 29, 2019, 10:46am UTC](https://discuss.ocaml.org/t/unimplemented-javascript-primitive-caml-pure-js-expr/3248 "2019-01-29T10:46:05Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Tie\_Cheng](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/tie_cheng/32/2076_2.png) [@Tie\_Cheng](https://discuss.ocaml.org/u/Tie_Cheng)\
**Post date:** [January 29, 2019, 10:46am UTC](https://discuss.ocaml.org/t/unimplemented-javascript-primitive-caml-pure-js-expr/3248/1 "2019-01-29T10:46:05Z")

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I have a project in OCaml that could be compiled in Ubuntu long time ago. Today, I want to pick up the project and try to compile it in `macOS Mojave 10.14.2`.

`ocaml --version` returns `The OCaml toplevel, version 4.07.1` , `js_of_ocaml --version` returns `3.3.0` , `npm --version` returns `6.7.0` , `node --version` returns `v8.9.3` .

`makefile` works fine and generates `analyze` . But `./analyze test.ev` returns `Unimplemented Javascript primitive caml_pure_js_expr!` .

Does anyone know where may be the problem?

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<div class="post-metadata">

**Author:** ![thangngoc89](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/thangngoc89/32/673_2.png) [@thangngoc89](https://discuss.ocaml.org/u/thangngoc89)\
**Post date:** [January 29, 2019, 3:28pm UTC](https://discuss.ocaml.org/t/unimplemented-javascript-primitive-caml-pure-js-expr/3248/2 "2019-01-29T15:28:42Z")

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> [@Tie\_Cheng](#):
>
> caml\_pure\_js\_expr

It looks like that you run the bytecode produced by ocamlc yourself? You need to compile the bytecode with js\_of\_ocaml first and uses node.js to run it