Sensor → native view → bridge → JS

One vertical slice, three layers

Before any code, hold the whole shape in your head. Data flows up from a sensor to your screen; configuration flows down from your screen to the sensor. You are building one vertical slice through three layers:

1. React Native (TypeScript/JSX) — <DepthScannerView onDepth={…} /> on a screen, plus a thin TS binding that names the native view.
2. The Expo Module definition — the View(...) { Prop, Events } DSL. This is the bridge you author.
3. The native view + sensor — a real UIKit/Android view hosting ARKit or ARCore, sampling depth.

In an interview, say: "A native module is one vertical slice: props flow down from JS to a native setter, events flow up from the sensor to a JS callback. Everything else is plumbing between those two directions."