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tools / react-native-debug

React Native Debug Pack

Analyze Metro logs, Hermes errors, bridge warnings, startup markers, and React Native stack traces.

P1Mobile DebuggingHigh severity
100
debug signal score
4 signals

4 signals detected. Start with hermes javascript error.

Detected signals

Hermes JavaScript error

A JS runtime failure appears in the React Native app.

Inspect the component stack, props, and API shape near the first app frame.

Metro bundler clue

Metro or module resolution may be failing.

Clear Metro cache only after checking import paths, package exports, and watchman state.

Native module issue

A native dependency may be missing, mislinked, or incompatible.

Check pods/Gradle install, new architecture support, and platform-specific module registration.

Startup performance marker

Startup timing data is present.

Compare JS bundle, native init, network boot, and first-render timings.

Highlighted lines
line 1
Metro waiting on exp://
Metro bundler clue
line 2
HermesInternal: TypeError undefined is not an object
Hermes JavaScript error
line 3
RCTFatalException
Native module issue
line 4
[Performance] JS bundle: 1800ms
Startup performance marker
Fix checklist
Inspect the component stack, props, and API shape near the first app frame.
Clear Metro cache only after checking import paths, package exports, and watchman state.
Check pods/Gradle install, new architecture support, and platform-specific module registration.
Compare JS bundle, native init, network boot, and first-render timings.
Separate Metro, JS runtime, and native logs.
Confirm Hermes/new architecture settings.
Reproduce on one simulator and one physical device when possible.

DebugTools product

React Native Debug Pack

React Native Debug Pack is a focused DebugTools mini-product for developers. Analyze Metro logs, Hermes errors, bridge warnings, startup markers, and React Native stack traces.

Use cases

  • Review mobile logs, crashes, startup, network, and device-specific clues.
  • Separate JavaScript, native, runtime, and platform evidence.
  • Capture a focused debugging report for mobile issue triage.

How it works

  • Paste or load the snippet you want to inspect in React Native Debug Pack.
  • Run the tool in the browser and review the highlighted output.
  • Copy, export, or turn the result into the next debugging step.

Privacy

  • React Native Debug Pack is local-first. The core workflow runs in your browser and does not require sending pasted content to DebugTools servers.

This tool history

Recent React Native Debug sessions

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