upload-video-to-instagram.js

import * as React from 'react';
import { Text, View, StyleSheet,TouchableOpacity,CameraRoll,Linking } from 'react-native';
import { Constants,FileSystem,Permissions } from 'expo';

export default class App extends React.Component {
  onPress = async () => {
    const filePath = `${FileSystem.documentDirectory}share-movie.mp4`;
    const res = await FileSystem.downloadAsync('http://techslides.com/demos/sample-videos/small.mp4', filePath);
    // const i = await FileSystem.getInfoAsync(res.uri);
    // console.log(i);

    const { status } = await Permissions.askAsync(Permissions.CAMERA_ROLL);
    if (status === 'granted') {
      try{
        const result = await CameraRoll.saveToCameraRoll(res.uri,"video");
        Linking.openURL(`instagram://library?AssetPath=${encodeURIComponent(result)}`);
      }
      catch(e){
        console.warn(JSON.stringify(e))
      }
    }
  }

  render() {
    return (
      <View style={styles.container}>
        <TouchableOpacity onPress={this.onPress}>
          <Text>download and getinfo</Text>
        </TouchableOpacity>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    alignItems: 'center',
    justifyContent: 'center',
    paddingTop: Constants.statusBarHeight,
    backgroundColor: '#ecf0f1',
  },
  paragraph: {
    margin: 24,
    fontSize: 18,
    fontWeight: 'bold',
    textAlign: 'center',
    color: '#34495e',
  },
});