I use: "dependencies": { "react": "16.3.1", "react-native": "0.55.4", "react-native-torch": "^1.1.4" }, ... import Torch from 'react-native-torch'; ... Torch.switchState(true); ... Same error in android: Possible Unhandled Promise Rejection(id:0): typeError:undefined is not an object(evaluating 'Torch.switchState')