@rpominov/bs-preserve-tags v0.1.1

PreserveTags

A hacky workaround to allow BuckleScript data structures to be transferred via JSON.

BuckleScript represents variants as JavaScript arrays with an added property tag, like so:

const arr = [1]; 
arr.tag = 0;

This representation cannot be transferred via JSON, if we do JSON.stringify(arr), the tag will be stripped. PreserveTags makes it possible:

let transfer = [%bs.raw
  {| function(x) {return JSON.parse(JSON.stringify(x))} |}
];

type t('a) =
  | A('a)
  | B('a);

/* Without PreserveTags B may become A */
transfer(B(1)) == A(1) /* true */

/* With PreserveTags it works fine */
PreserveTags.decode(transfer(PreserveTags.encode(B(1)))) == B(1) /* true */

API

module PreserveTags = {
  type t('a);
  let encode: 'a => t('a);
  let decode: t('a) => 'a;
}

Installation

npm i @rpominov/bs-preserve-tags

Then in your bsconfig.json:

"bs-dependencies": ["@rpominov/bs-preserve-tags"]