expo-atlas/README.md

Inspect bundle contents, on module level, from Metro

# Expo Atlas

Inspect your Metro bundle, on module level.

> [!Warning]
> This project is unstable and might not work for your project.

## 🚀 How to use it

Atlas is built into Expo starting from SDK 51, and enabled when defining the environment variable `EXPO_UNSTABLE_ATLAS=true`.

You can use Atlas with two Expo commands:
- `$ expo start` → Start a local dev server, Atlas will listen to any change within your project.
- `$ expo export` → Export your app to Android, iOS, or web. Atlas will generate the `atlas.jsonl` file.

### Using `$ expo start`

When enabling Atlas with the local dev server, you can access Atlas on [http://localhost:8081/_expo/atlas](http://localhost:8081/_expo/atlas). This shows you all information from the bundle loaded during development.

```bash
$ EXPO_UNSTABLE_ATLAS=true npx expo start
```

> [!TIP]
> Expo start runs in development mode by default. If you want to see a production bundle of your app, you can start the local dev server in production mode: `$ expo start --no-dev --no-minify`.

### Using `$ expo export`

When enabling Atlas during exports, Expo generates the `.expo/atlas.json` file in your project. This file contains all bundle information, including the actual source code of individual files. You can open the Atlas file through `npx expo-atlas [path/to/atlas.jsonl]`.

```bash
# Export the app for all platforms
$ EXPO_UNSTABLE_ATLAS=true npx expo export --platform all

# Open Atlas using the default `.expo/atlas.jsonl` path
$ npx expo-atlas
# Open Atlas from a shared file
$ npx expo-atlas ./path/to/atlas.jsonl
```

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  with&nbsp;❤️&nbsp;&nbsp;<strong>Expo</strong>
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