react-native-sync-background

Intelligent Job-Scheduling port to React Native: Scheduling data background synchronizations that run in your JavaScript.

Read a broader introduction in the following post: React Native and Native Modules: The Android SyncAdapter

Requirements

React Native 0.36+

Pros

Under the hood, this library uses a SyncAdapter:

Android will trigger a sync using our syncFlexTime to decide when is the best moment to do so (battery efficiency)
No need to worry about internet connection
No need to worry about the user restarting the device
Compatible with all Android versions supported by RN (4.1+)

Caveats

No iOS support:

To run tasks on the background using JavaScript, this library uses Headles JS which is currently supported only on Android. You can vote for the related issue here

App in the foreground:

Syncs will only trigger if the app is not in the foreground. Check out the blog post mentioned above to read more about this and how to mitigate it

Getting started

yarn add react-native-sync-background

Installation

react-native link react-native-sync-background

Manual Android required step

Open up the string.xml file of your Android project. You need to add the following (just change the content):

<string name="app_name">YourAppName</string>
<string name="rnsb_sync_account_type" translatable="false">your.android.package.name</string>
<string name="rnsb_content_authority" translatable="false">your.android.package.name.provider</string>

This will override the default values from the library and make them unique for your app.

Usage

You need to register a task with a specific name and only with this specific name: TASK_SYNC_BACKGROUND. You should do it in the same place where you register your app:

AppRegistry.registerComponent('MyApp', () => MyApp);
AppRegistry.registerHeadlessTask('TASK_SYNC_BACKGROUND', () => TestTask);

Then, on your top most component:

import SyncBackground from 'react-native-sync-background';

...

componentDidMount() {
  SyncBackground.init({
    syncInterval,
    syncFlexTime,
  });
}

...

That is all!

API

init

Schedules background syncs within your app.

Object: {
  syncInterval: number;
  syncFlexTime: number;
}

syncInterval: The amount of time in seconds that you wish to elapse between periodic syncs
syncFlexTime: The amount of flex time in seconds before syncInterval that you permit for the sync to take place. Must be less than syncInterval

A good example could be syncInterval: 12 * 60 * 60 (12 hours) and syncFlexTime: 0.5 * 60 * 60 (30 minutes).

Notice that syncFlexTime only works for Android 4.4+, for older versions, that value will be ignored and syncs will be always exact.

Running example

You can try this library running the example app:

cd example && npm install

Then just run:

react-native run-android

Be careful: The installed app will trigger a sync around every minute (so it is easy to see that is working). If you debug the app, you should be able to see the HeadlessJS ouputing: Headless JS task was fired! (remember not to have the app on the foreground). After you try it, I recommend to uninstall the app so you don't harm your device battery life.

hkairi/react-native-sync-background