Realm by MongoDB is an offline-first mobile database: an alternative to SQLite and key-value stores
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 (JSC & Hermes on iOS & Android), Node.js and Electron (on Windows, MacOS and Linux).
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 13 or later is supported. For React Native users, we have a compatibility matrix showing which versions are supported.
It is exciting to have users, and we want to support you as good as possible. Our community support (Github issues in this and our related repositories) is divided into three tiers, and below you can see which packages, versions and platforms we consider for the different tiers.
If you want to contribute to any of our packages, you are welcome to do so. We will take the time to review your pull request for any package.
In tier 1 we will respond to issues in a timely manner during workdays from CET timezone, and we will work on bug fixing and adding new features.
latest) on node.js (LTS) and Electron on Windows, MacOS, and Linuxlatest) with the latest React Native version 0.71.0 on Android and iOSlatest) in conjunction with the latest Realm JavaScript releaseSome packages are considered to be mature and stable, and we will support them as good as we can when time permits.
latest)The third tier covers our experimental packages. We work on them occasionally, and they are likely to change radically when we do.
The documentation for the Realm React Native SDK can be found at mongodb.com/docs/realm/sdk/react-native/. The documentation for Realm Node.js SDK can be found at mongodb.com/docs/realm/sdk/node.
The API reference is located at docs.mongodb.com/realm-sdks/js/latest/.
If you are using React Native, please also take a look the README for @realm/react, which provides React hooks to make working with Realm easier.
TypeScript is a popular alternative to pure JavaScript as it provide static typing. Our TypeScript support consists of two parts
class Task extends Realm.Object<Task, "description"> {
_id = new Realm.BSON.ObjectId();
description!: string;
@index
isComplete = false;
static primaryKey = "_id";
constructor(realm, description: string) {
super(realm, { description });
}
}
Realm is a general SDK which provide you persistence of objects and the capability to perform advanced queries on the objects. You can have tighter integration with React Native by using @realm/react.
Moreover, we have a Flipper plugin to help you inspect, query and modify your Realm files while debugging your app on a simulator or a physical device. The plugin is still in an early stage so expect rough edges.
We have TypeScript templates to help you get started using Realm. Follow the links to your desired template and follow the instructions there to get up and running fast.
See CONTRIBUTING.md for more details!
Debug with Chrome in the Debug Menu.For instructions on building Realm JS yourself from the source, see the building.md file.
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 https://github.com/realm/realm-js/issues/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.
It's possible after installing and running Realm that one encounters the error Could not find the Realm binary. Here are are some tips to help with this.
Consult our COMPATIBILITY.md to ensure you are running compatible version of realm with the supported versions of node, react-native or expo.
Typically this error occurs when the pod dependencies haven't been updating. Try running the following command
npx pod-install
If that still doesn't help it's possible there are some caching errors with your build or your pod dependencies. The following commands can be used to safely clear these caches:
rm -rf ios/Pods
rm ios/Podfile.lock
rm -rf ~/Library/Developer/Xcode/DerivedData
Afterwards, reinstall pods and try again. If this still doesn't work, ensure that node_modules/realm/react-native/ios/realm-js-ios.xcframework exists and contains a binary for your architecture. If this is missing, try reinstalling the `realm`` npm package.
This can occur when installing realm and not performing a clean build. The following commands can be used to clear your cache:
cd android
./gradlew clean
Afterwards, try and rebuild for Android. If you are still encountering problems, ensure that node_moduels/realm/react-native/android/src/main/jniLibs contains a realm binary for your architecture. If this is missing, try reinstalling the realm npm package.
If you are using Expo, a common pitfall is not installing the expo-dev-client and using the Development Client specific scripts to build and run your React Native project in Expo. The Development Client allows you to create a local version of Expo Go which includes 3rd party libraries such as Realm. If you would like to use realm in an Expo project, the following steps can help.
expo-dev-client:
npm install expo-dev-client
npx expo run:ios
npx expo run:android
npx expo start --dev-client
When running npm install realm the realm binaries for the detected architecture are downloaded into node_modules/realm/prebuilds. If this directory is missing or empty, ensure that there weren't any network issues reported on installation.
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:
Moreover, we unconditionally write various constants to a file which we might use at runtime.
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.
Realm JS and Realm Core are published under the Apache License 2.0.
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!
Made with contrib.rocks.
12.5.0 (2023-12-19)
keyPaths argument to the addListener methods of Collection and Object. Use this to indicate a lower bound on the changes relevant for the listener. This is a lower bound, since if multiple listeners are added (each with their own "key paths") the union of these key-paths will determine the changes that are considered relevant for all listeners registered on the object or collection. In other words: A listener might fire more than the key-paths specify, if other listeners with different key-paths are present. (#6285)
// Adding a listener that will fire only on changes to the `location` property (if no other key-path listeners are added to the collection).
cars.addListener((collection, changes) => {
console.log("A car location changed");
}, ["location"]);
!m_sess assertion. (realm/realm-core#7196, since v10.18.0)SyncSession was explicitly resumed via reconnect() while it was waiting to auto-resume after a non-fatal error and then another non-fatal error was received, the sync client could crash with a !m_try_again_activation_timer assertion. (realm/realm-core#6961, since device sync was introduced)Collection or Object used to be undefined behavior. Now it throws, which results in runtime errors that can be resolved by ensuring that the callback is only added once per object. (#6310)FAQs
Realm by MongoDB is an offline-first mobile database: an alternative to SQLite and key-value stores
The npm package realm receives a total of 28,930 weekly downloads. As such, realm popularity was classified as popular.
We found that realm demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 5 open source maintainers collaborating on the project.
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