App.js

import React, { Component } from 'react';
import { Platform, StyleSheet, Text, View, Alert } from 'react-native';
import * as Permissions from 'expo-permissions';
import * as ImagePicker from 'expo-image-picker';

const instructions = Platform.select({
  ios: 'Press Cmd+R to reload,\n' + 'Cmd+D or shake for dev menu',
  android: 'Double tap R on your keyboard to reload,\n' + 'Shake or press menu button for dev menu',
});

export default class App extends Component {
  launchCamera = async () => {
    console.log("checking permissions")
    
    try {
      const { status } = await Permissions.askAsync(Permissions.CAMERA, Permissions.CAMERA_ROLL);
      if (status !== "granted") {
        throw new Error("You MUST grant permissions for this demo app to work!")
      } else {
        console.log("Permissions granted!")
      }

      await ImagePicker.launchCameraAsync({
        allowsEditing: true,
        aspect: [1, 1],
        quality: 0.9,
        base64: true,
      }).then(() => Alert.alert("Yayyy, we took a photo!"))
    } catch (e) {
      Alert.alert(e.message);
    }
  }

  async componentDidMount() {
    await this.launchCamera();
  }

  render() {
    return (
      <View style={styles.container}>
        <Text style={styles.welcome}>Welcome to React Native!</Text>
        <Text style={styles.instructions}>To get started, edit App.js</Text>
        <Text style={styles.instructions}>{instructions}</Text>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  welcome: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
  instructions: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5,
  },
});