Migrate to ReScript 11

Minimal Migration

This guide describes the things to do at least to migrate to ReScript 11.

Disable uncurried mode

If you use currying extensively and don't want to bother with adapting your code (or have dependencies )

JSON
{
  "uncurried": false
}

Recommended Migration

Uncurried Mode

For uncurried mode to take effect in ReScript 11 there is nothing to configure, it is activated by default.

Adapt suffix

ReScript 11 now allows having arbitrary suffixes in the generated JavaScript files. However it is still recommended to stick to using .res.js, .res.mjs or .res.cjs. For more information, read the Build System Configuration about suffixes.

rescript.json

The old configuration filename bsconfig.json is finally deprecated. Rename it to rescript.json.

ReScript-Core standard library

There is a new standard library in development that can already be installed called ReScript-Core. It replaces the complete Js module as well as some of the more frequently used modules from Belt and is the recommended standard library to use with uncurried mode. At a later stage it will be integrated into the compiler while Belt will be maintaned as a separate npm package.

Until it's integrated in the compiler, it needs to be installed manually:

CONSOLE
$ npm install @rescript/core

Then add @rescript/core to your rescript.json's dependencies:

DIFF
 {
   "bs-dependencies": [
+    "@rescript/core"
   ]
 }

Open it so it's available in the global scope.

DIFF
 {
   "bsc-flags": [
+    "-open RescriptCore",
   ]
 }

For a detailed explanation on migration to ReScript-Core, please refer to its migration guide. A semi-automated script is available as well.

Note: ReScript-Core API docs will be added to this documentation platform at a later stage. For now check out the .resi files in the repository or, more conveniently, read the docs for a certain module or function directly in the editor tooling.

Removed bindings

Many Node bindings have been removed from the compiler. Please use rescript-nodejs instead or write your own local bindings.