# Unmarshalling in Js\_of\_ocaml data serialized using native OCaml marshalling

**URL:** <https://discuss.ocaml.org/t/unmarshalling-in-js-of-ocaml-data-serialized-using-native-ocaml-marshalling/14294>\
**Category:** Community\
**Tags:** js\_of\_ocaml\
**Created:** [March 13, 2024, 3:47pm UTC](https://discuss.ocaml.org/t/unmarshalling-in-js-of-ocaml-data-serialized-using-native-ocaml-marshalling/14294 "2024-03-13T15:47:42Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![charguer](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/charguer/32/2199_2.png) [@charguer](https://discuss.ocaml.org/u/charguer)\
**Post date:** [March 13, 2024, 3:47pm UTC](https://discuss.ocaml.org/t/unmarshalling-in-js-of-ocaml-data-serialized-using-native-ocaml-marshalling/14294/1 "2024-03-13T15:47:42Z")

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Hi,

I have a big OCaml data structure produced by a native OCaml application, that I marshall into a file.

I would like to load the contents of this data structure into a browser, for manipulation using JavaScript code, to interactively display relevant pieces of information in response to user queries.

First question: I can invoke OCaml’s unmarshall function from Js\_of\_ocaml?

Second question: if my data structure involves a fair amount of sharing, do I have any hope that unmarshalling in JS would preserve the sharing? If not, any idea on how to convert an OCaml data structure with sharing into a corresponding JS data structure featuring the same sharing?

Thanks!

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**Author:** ![nojb](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/nojb/32/519_2.png) [@nojb](https://discuss.ocaml.org/u/nojb)\
**Post date:** [March 13, 2024, 4:13pm UTC](https://discuss.ocaml.org/t/unmarshalling-in-js-of-ocaml-data-serialized-using-native-ocaml-marshalling/14294/2 "2024-03-13T16:13:18Z")

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> [@charguer](#):
>
> First question: I can invoke OCaml’s unmarshall function from Js\_of\_ocaml?

Yes.

> [@charguer](#):
>
> Second question: if my data structure involves a fair amount of sharing, do I have any hope that unmarshalling in JS would preserve the sharing?

Yes.

Cheers,  
Nicolas

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<div class="post-metadata">

**Author:** ![charguer](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/charguer/32/2199_2.png) [@charguer](https://discuss.ocaml.org/u/charguer)\
**Post date:** [March 14, 2024, 3:17pm UTC](https://discuss.ocaml.org/t/unmarshalling-in-js-of-ocaml-data-serialized-using-native-ocaml-marshalling/14294/3 "2024-03-14T15:17:46Z")

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Great, thanks! I will give it a try then.

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**Author:** ![dbuenzli](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.ocaml.org/dbuenzli/32/18_2.png) [@dbuenzli](https://discuss.ocaml.org/u/dbuenzli)\
**Post date:** [March 14, 2024, 3:44pm UTC](https://discuss.ocaml.org/t/unmarshalling-in-js-of-ocaml-data-serialized-using-native-ocaml-marshalling/14294/4 "2024-03-14T15:44:00Z")

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The full details about `js_of_ocaml` and OCaml marshaling are on [this page](https://ocsigen.org/js_of_ocaml/latest/manual/overview).