Realm is a mobile database that runs directly inside phones, tablets or wearables. This project hosts the JavaScript versions of Realm. Currently we support React Native (both iOS & Android), Node.js and Electron (on Windows, MacOS and Linux).

Features

• Mobile-first: Realm is the first database built from the ground up to run directly inside phones, tablets and wearables.
• Simple: Data is directly exposed as objects and queryable by code, removing the need for ORM's riddled with performance & maintenance issues.
• Modern: Realm supports relationships, generics, and vectorization.
• Fast: Realm is faster than even raw SQLite on common operations, while maintaining an extremely rich feature set.

Getting Started

Please see the detailed instructions in our docs to use Realm JavaScript for Node.js and Realm JavaScript for React Native. Please notice that currently only Node.js version 10 or later (excluding 11) are supported.

Documentation

Realm React Native and Node.js

The documentation for the Realm React Native SDK can be found at docs.mongodb.com/realm/sdk/react-native/. The documentation for Realm Node.js SDK can be found at docs.mongodb.com/realm/sdk/node.

The API reference is located at docs.mongodb.com/realm-sdks/js/latest/.

Template apps for React Native

To get started with Realm JS for React Native, we have provided a simple template app.

To create a new app with Expo:

npx create-react-native-app --template with-realm ExpoExample

To create a new app from the TypeScript template:

npx react-native init TsExample --template @realm/react-native-template-ts

To create a new app from the JavaScript template:

npx react-native init JsExample --template @realm/react-native-template-js

Getting Help

• Need help with your code?: Look for previous questions on the #realm tag — or ask a new question. You can also check out our Community Forum where general questions about how to do something can be discussed.
• Have a bug to report? Open an issue. If possible, include the version of Realm, a full log, the Realm file, and a project that shows the issue.
• Have a feature request? Open an issue. Tell us what the feature should do, and why you want the feature.

Known issues

• Realm is not compatible with the Chrome Debugger. The following debugging methods are supported.
  • Flipper has many similar features in relation to the Chrome Debugger. Please consider trying out our Hermes release to use the Hermes Debugger in Flipper and set breakpoints in your code.
  • Safari also has a similar feature set, but requires some setup and only supports debugging in iOS.
  • NOTE: For the above methods, it is not neccessary to enable Debug with Chrome in the Debug Menu.

Building Realm JS

For instructions on building Realm JS yourself from source, see the building.md file.

Issues with debugging

Some users have reported the Chrome debugging being too slow to use after integrating Realm into their react-native project. This is due to the blocking nature of the RPC calls made through the Realm library. See realm#491 for more information. The best workaround is to use Safari instead, as a user has described here.

Moreover, we have a switch to Flipper in the works as part of our effort to support Hermes. It implies that we envision a near future where the Chrome debugging will be removed, and we currently don't invest much in its maintenance.

Analytics

Asynchronously submits install information to Realm.

Why are we doing this? In short, because it helps us build a better product for you. None of the data personally identifies you, your employer or your app, but it will help us understand what language you use, what Node.js versions you target, etc. Having this info will help prioritizing our time, adding new features and deprecating old features. Collecting an anonymized application path & anonymized machine identifier is the only way for us to count actual usage of the other metrics accurately. If we don’t have a way to deduplicate the info reported, it will be useless, as a single developer npm install-ing the same app 10 times would report 10 times more than another developer that only installs once, making the data all but useless. No one likes sharing data unless it’s necessary, we get it, and we’ve debated adding this for a long long time. If you truly, absolutely feel compelled to not send this data back to Realm, then you can set an env variable named REALM_DISABLE_ANALYTICS.

Currently the following information is reported:

• What version of Realm is being installed.
• The OS platform and version which is being used.
• Node.js, v8, libuv, OpenSSL version numbers.
• An anonymous machine identifier and hashed application path to aggregate the other information on.

Code of Conduct

This project adheres to the MongoDB Code of Conduct. By participating, you are expected to uphold this code. Please report unacceptable behavior to community-conduct@mongodb.com.

Contributing

See CONTRIBUTING.md for more details!

License

Realm JS and Realm Core are published under the Apache License 2.0.

This product is not being made available to any person located in Cuba, Iran, North Korea, Sudan, Syria or the Crimea region, or to any other person that is not eligible to receive the product under U.S. law.

Feedback

If you use Realm and are happy with it, all we ask is that you please consider sending out a tweet mentioning @realm to share your thoughts

And if you don't like it, please let us know what you would like improved, so we can fix it!