---
title: Code coverage for React Native - Typescript, iOS, and Android - without touching the native stuff.
description: Flush real device coverage from a TurboModule, merge it into LCOV / Jacoco, remap TypeScript line-for-line, and gate your dev loop or CI.
---

Install it into a dedicated test / e2e harness app ([Pattern C](/pattern-c)) — never your shipping app.

A TurboModule flushes real device coverage; the CLI pulls it, **merges** every framework's `.profraw` and the
app binary into clean LCOV / Jacoco, and remaps your instrumented JS line-for-line back to TypeScript — smoothing
the rough edges of modern TypeScript development by handling the line-accurate source mapping for you. Use that as
a signal in your development loop or CI to gate development iterations or CI pass/fail.

[![Codecov dashboard for react-native-coverage — overall coverage, 3-month trend, sunburst graph, and the native code tree](/assets/codecov/dashboard.png)](https://app.codecov.io/gh/invertase/react-native-coverage)

## Start here

<CardGroup cols={3}>
  <Card title="App developers" icon="mobile-screen" href="/app-developers">
    Add native coverage to your Expo or React Native CLI test app.
  </Card>
  <Card title="Library maintainers" icon="cubes" href="/library-maintainers">
    Prove your library's native code ran — in unit tests and a test app.
  </Card>
  <Card title="Agents" icon="robot" href="/agents">
    A paste-ready prompt and the CI contract your agent must satisfy.
  </Card>
</CardGroup>

## Why it matters

React Native is cross-platform, but coverage tooling usually stops at the JavaScript bundle.
The Objective-C++, Swift, and Kotlin behind your TurboModules run on a device and then vanish —
**iOS native coverage especially is a black box.** This package makes that evidence a one-liner,
so you (or your agent) can prove the native path executed, not just the mock.

[Read the full rationale →](/why)

## Proof, live on `main`

This repository proves its own thesis on Codecov — including the hard part, iOS:

| Flag | What ran | Coverage |
|------|----------|---------:|
| `e2e-ios-dynamic` | iOS native, dynamic frameworks | **90.6%** |
| `e2e-android` | Android native (Emma → Jacoco) | **81.7%** |
| `e2e-ios-static` | iOS native, static libraries | **63.1%** |
| `unit-js` | Jest unit (JS/TS) | **52.6%** |

[Browse it on Codecov →](https://app.codecov.io/gh/invertase/react-native-coverage)

## Used in production by

Both [**React Native Firebase**](https://github.com/invertase/react-native-firebase) and
[**React Native Google Mobile Ads**](https://github.com/invertase/react-native-google-mobile-ads)
depend on `react-native-coverage` in their [Pattern C](/pattern-c) test apps.

<p>
  <a href="https://github.com/invertase/react-native-firebase">
    <img src="/assets/consumers/react-native-firebase.png" alt="React Native Firebase" height="56" />
  </a>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
  <a href="https://github.com/invertase/react-native-google-mobile-ads">
    <img src="/assets/consumers/react-native-google-mobile-ads.svg" alt="React Native Google Mobile Ads" height="56" />
  </a>
</p>

## What you get

| Piece | Role |
|-------|------|
| **TurboModule** | `flush()` — iOS LINKEDIT LLVM flush + Android Emma dump (also dumps Istanbul `global.__coverage__` when present) |
| **CLI (`rn-coverage`)** | `android pull\|report`, `ios pull\|export\|report\|summary`, `js pull\|report`, `assert` |
| **Expo config plugin** | Wires the Gradle helpers + the Podfile helper call |
| **CocoaPods Ruby helper** | Pod LLVM flags + optional dynamic-framework restore |
| **Gradle Jacoco helpers** | `android/rn-coverage.gradle` + `android/rn-coverage-jacoco.gradle` |
| **JS/TS coverage** | `babel-plugin-istanbul` + NYC source-map remap → TypeScript-accurate LCOV |