I can't make run the blemanager.start because promise rejection id:0 null is not an object

Question

I can't start the ble manager in my code. I use expo. I tried a lot of solutions I found on internet but none worked for me. When i get out the blemanager.start my app run correctly. I don't find any kind of doc about promise in React native... There is my code. I really hope you can help me.

import { Stylesheet, View, Text, Button, TouchableOpacity,FlatList, Alert,NativeAppEventEmitter } from 'react-native'
import donnee from '../Donnee/data'
import DataItem from './DataItem'
import FilmDetail from './FilmDetail';
import BleManager from 'react-native-ble-manager';
import React, { useState, useEffect } from 'react';
//import BleManager from 'react-native-ble-plx';
const width_proportion = '60%';
const Lwidth_proportion = '30%';
const maxwidth="100%";
const heightinside="12%";
const paddleft = '10%';
class Search extends React.Component {
  componentDidMount() {
    console.log('bluetooth scanner mounted');
    NativeAppEventEmitter.addListener('BleManagerDiscoverPeripheral',(data) => 
    {
        let device = 'device found: ' + data.name + '(' + data.id + ')'; 
        if(this.devices.indexOf(device) == -1) {
            this.devices.push(device);
        }
        let newState = this.state;
        newState.dataSource = newState.dataSource.cloneWithRows(this.devices);
        this.setState(newState);
    });
    BleManager.start({ showAlert: false }).then(() => {
        // Success code
        console.log("Module initialized");
      });
}
  startScanning() {
    console.log('start scanning');
}
    render() {
        return (
        <View>
          <View style={styles.entete}></View>
          <View>
            <TouchableOpacity style = {styles.filtrebtn}  onPress={() => this.props.navigation.navigate("FilmDetail")}>
              <Text style = {styles.textfiltre}>FILTRES</Text>
            </TouchableOpacity>
            <TouchableOpacity style = {styles.scan}  onPress={() => this.startScanning()}>
              <Text style = {styles.textscan}>SCAN</Text>
            </TouchableOpacity>
          </View>
          <View>
               <FlatList 
               data={donnee} 
               keyExtractor={(item) => item.id.toString()} 
               renderItem={({item}) =><DataItem donnees={item}/> }  />
          </View>
        </View>
          
        )
    }
}
export default Search

Answer 1

expo can not work with the ble-manager. You need to use the native package by running the

npx react-native init AwesomeProject

and you need mac not a window