app.js

import React, { Component } from 'react'
import {
                StyleSheet,
                Text,
                View,
                TouchableOpacity,
                Platform,
                Image,
                ActivityIndicator,YellowBox
        } from 'react-native'
import ImagePicker from 'react-native-image-picker';
import RNFetchBlob from 'react-native-fetch-blob';
import firebase from 'firebase';
import _ from 'lodash';

              YellowBox.ignoreWarnings(['Setting a timer']);
              const _console = _.clone(console);
              console.warn = message => {
                if (message.indexOf('Setting a timer') <= -1) {
                  _console.warn(message);
                  Alert.alert(
                'Alert Title',
                'My Alert Msg',
                [
                  {text: 'Try again'},
                  {text: 'OK', onPress: () => console.log('OK Pressed')},
                ],
                {cancelable: false},
              );
                }
              };

// Init Firebase
          var firebaseConfig = {
              apiKey: "Something",
              authDomain: "Your_Auth_Domain",
              databaseURL: "Your_database_url",
              projectId: "Your_project_id",
              storageBucket: "Your_bucket",
              messagingSenderId: "Your_id",
              appId: "_App_ID_"
            };
            // Initialize Firebase
          firebase.initializeApp(firebaseConfig);
          const storage = firebase.storage()
          const Blob = RNFetchBlob.polyfill.Blob
          const fs = RNFetchBlob.fs
          window.XMLHttpRequest = RNFetchBlob.polyfill.XMLHttpRequest
          window.Blob = Blob

          const uploadImage = (uri, mime = 'application/octet-stream') => {
            return new Promise((resolve, reject) => {
              const uploadUri = Platform.OS === 'ios' ? uri.replace('file://', '') : uri
              const sessionId = new Date().getTime()
              let uploadBlob = null
              const imageRef = storage.ref('images').child(`${sessionId}`)

              fs.readFile(uploadUri, 'base64')
                .then((data) => {
                  return Blob.build(data, { type: `${mime};BASE64` })
                })
                .then((blob) => {
                  uploadBlob = blob
                  return imageRef.put(blob, { contentType: mime })
                })
                .then(() => {
                  uploadBlob.close()
                  return imageRef.getDownloadURL()
                })
                .then((url) => {
                  resolve(url)
                })
                .catch((error) => {
                  reject(error)
              })
            })
          }


class Upload extends Component {
  constructor(props) {
    super(props)

    this.state = {}
  }

  _pickImage() {
    this.setState({ uploadURL: '' })

    ImagePicker.launchImageLibrary({}, response  => {
      uploadImage(response.uri)
        .then(url => this.setState({ uploadURL: url }))
        .catch(error => console.log(error))
    })
  }

  render() {
    return (
      <View style={ styles.container }>
        {
          (() => {
            switch (this.state.uploadURL) {
              case null:
                return null
              case '':
                return <ActivityIndicator />
              default:
                return (
                  <View>
                    <Image
                      source={{ uri: this.state.uploadURL }}
                      style={ styles.image }
                    />
                    <Text> Please Wait </Text>
                  </View>
                )
            }
          })()
        }
        <TouchableOpacity onPress={ () => this._pickImage() }>
          <Text style={ styles.upload }>
            Upload
          </Text>
        </TouchableOpacity>
      </View>
    )
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  image: {
    height: 200,
    resizeMode: 'contain',
  },
  upload: {
    textAlign: 'center',
    color: '#333333',
    padding: 10,
    marginBottom: 5,
    borderWidth: 1,
    borderColor: 'gray'
  },
})

export default Upload