Reasonable React Native

Wheeler argues that building complex applications in JavaScript can feel unreasonable, and introduces Reason as a typed syntax and toolchain for OCaml that feels familiar to JavaScript developers. He highlights static types, type inference, native compilation, and the ability to adopt Reason incrementally alongside existing JavaScript.

Wheeler walks through familiar primitives, block-scoped let bindings, and Reason’s module system, where each file acts as a module and names are accessed with dot notation. He also covers function shorthand, labeled arguments, records, variants, and pattern matching, including variants for idle, loading, and error states.

BuckleScript compiles Reason and OCaml to readable JavaScript and provides interop through typed external declarations. Wheeler then explains ReasonReact components, props, text conversion, and state updates, which use updater functions returning a new state or a no-update result.

Wheeler recommends the community’s BSReactNative bindings so developers can use pre-typed React Native APIs. The bindings represent many style values as language-level enums, enabling completion and rejecting unsupported values such as an invalid style property.

Wheeler describes building the Seattle JS conference React Native app in Reason over two weeks and says it included a modal animation that opened from an item’s position. He outlines setup with a React Native app, bs-platform, bs-react-native, reason-react, a BuckleScript config, and build and watch scripts; the JavaScript app entry point imports the compiled Reason component.