Experimental support for ongoing background jobs

A new parameter, alwaysRunning is added to the schedule function and this will allow the app to run forever and prevent the system from killing it. To allow this, Android requires the app to show a notification.

Note: This will not work or at least act unexpectedly with multiple background jobs, currently only one job is supported. PR's fixing this are welcome but for our company's use-case it is not a priority.

This is not on master yet since it is very experimental, see the README.md on the feature branch.

Install with

yarn add react-native-background-job@beta