React Native HelloWorld

This is a React Native application developed in Reason.

Please carefully read instructions below in order to enjoy ReasonML development experience.

Setup

Start a Reason React Native project with this template

react-native init MyApp --template reason

Command line

Install BuckleScript with the following command:

yarn add bs-platform --dev

IDE

To get the best development experience possible, we recommend you to use VSCode with Reason Language Server extension & optionally Flow Language Server extension if you have JavaScript covered by Flow.

If you won't want to use VSCode, at least get a ReasonML editor plugin.

package.json

To get started, add the following scripts to your package.json:

"scripts": {
  "re:watch": "bsb -clean-world -make-world -w",
  "re:build": "bsb -clean-world -make-world",
  "start": "node node_modules/react-native/local-cli/cli.js start",
  "start:ios": "react-native run-ios",
  "start:android": "react-native run-android",
}

Note: you probably have start already.

Development workflow

Note: yarn can be replaced by npm run in all commands below.

Depending on your editor & its ReasonML integration you might need to use:

yarn re:watch

Reminder: this step might be unecessary if your editor can handle ReasonML compilation by its own. Read more.

As soon as .re files are being compiled to .bs.js, you can either start the project on iOS Simulator (included in Xcode) or an Android Emulator (if you are unfamiliar with Android Studio, you might be interested by Genymotion).

yarn start:ios

or

yarn start:android

This commands should open up a virtual device & start React Native metro bundler. This packager will serves the compiled Reason code to the React Native client.

Now you can start coding by editing files in src/!

Read more about starting the project in your environment of choice.

Note: as soon as you have the app installed in a simulator/emulator, you could just run

yarn start

This avoid rebuilding the entire native parts & will just start React Native metro bundler.

Breakdown of existing files

The react-native init command generates a lot of boilerplate with files that might be not needed for your particular use case. Below is a breakdown of all top-level files to help you decide:

• .babelrc - required, for transpiling Javascript files to supported by the mobile engine Javascript version
• .buckconfig - optional, configuration files for Buck. Can be safely removed in most cases unless you are planning on using it
• .flowconfig - optional, used to configure Flow, which is a type checker for Javascript. Can be removed as you are writing our code in Reason
• .watchmanconfig - optional, configuration for Watchman, which is a Facebook tool for listening to file system changes. This file is not needed, unless you plan on extending its configuration