What's the correct way of passing data/props to TaskManager/BackgroundFetch

[sunney]

Please provide the following:

1. SDK Version: ~45.0.0
2. Platforms(Android/iOS/web/all): Android
3. Add the appropriate “Tag” based on what Expo library you have a question on.

I’m building a bus transportation app where users can subscribe to the arrival time of a certain bus.

Basically, the user should be able to subscribe to some bus’s arrival time and get notifications every minute.

I made it using the expo-notifications, but I also want it to be able to work in the background.

I tried using the TaskManager and BackgroundFetch, but documentation doesn’t explicitly provide a way to pass props/data to a defined task.

Basically the flow should work like this:

User opens app → subscribes to bus #55 → should receive a notification about bus #55’s arrival time every minute in background.

I’m struggling with the part of passing the bus number to the task.

[keith-kurak]

If you want BackgroundFetch to work based on a particular piece of user-defined data, you would want to store that data in a global location (e.g., in AsyncStorage), and then have a single background task registered that reads the data from that global location and performs the corresponding tasks.

In this particular case, it’s likely you’ll be better-served by not using a background task at all, but rather sending notifications from a server. The mobile OS tends to limit how often a task can run in the background, and once per minute may be too often.