how to make the blur effect with react-native?

Now you can do this without any library using the prop: blurRadius.

E.g

<Image
    style={styles.img}
    resizeMode='cover'
    source={imgSrc} 
    blurRadius={1}
/>

Explanation: the number(1) means the amount of blur you want to apply on the image, the higher the number, the blurrier the image.

Unfortunately, this doesn't work on Android yet (RN 0.40.0). Nevertheless, it could be useful to who's looking for only an iOS solution.

Edit: It seems to be working on Android now.

Try using {ImageBackground} from 'react-native' and set blurRadius={number} like this:

<ImageBackground
      style={{flex: 1}}
      source={require('../assets/example.jpg')}
      blurRadius={90}>
    <Text>Blur background<Text>
</ImageBackground>

https://facebook.github.io/react-native/docs/images.html#background-image-via-nesting https://facebook.github.io/react-native/docs/image.html#blurradius

To blur and an entire View in react-native you can use @react-native-community/blur and apply it like this:

import React, { Component } from 'react';
import { BlurView } from '@react-native-community/blur';
import {
  StyleSheet,
  Text,
  View,
  findNodeHandle,
  Platform,
  Image,
} from 'react-native';

const styles = StyleSheet.create({
  title: {
    color: 'black',
    fontSize: 15,
  },
  absolute: {
    position: 'absolute',
    top: 0,
    left: 0,
    bottom: 0,
    right: 0,
  },
  blurredView: {
    // For me android blur did not work until applying a background color:
    backgroundColor: 'white',
  },
});

export default class MyBlurredComponent extends Component {
  constructor(props) {
    super(props);
    this.state = { viewRef: null };
  }

  onTextViewLoaded() {
    this.setState({ viewRef: findNodeHandle(this.viewRef) });
  }

  render() {
    return (
      <View>
        <View
          style={[
            styles.blurredView,
          ]}
          ref={(viewRef) => { this.viewRef = viewRef; }}
          onLayout={() => { this.onTextViewLoaded(); }}
        >
          <Image
            style={{ width: 100, height: 100 }}
            source={{ uri: 'https://facebook.github.io/react-native/docs/assets/GettingStartedCongratulations.png' }}
          />
          <Text style={[styles.title]}>
            TEXT 2222 \n
            TEXT 3333
          </Text>
        </View>
        {
          (this.state.viewRef || Platform.OS === 'ios') && <BlurView
            style={styles.absolute}
            viewRef={this.state.viewRef}
            blurType="light"
            blurAmount={3}
            blurRadius={5}
          />
        }
      </View>
    );
  }
}

// Deps:

 "react-native": "0.53.3",
 "@react-native-community/blur": "^3.2.2"

Result:

Install react-native-blur:

npm install react-native-blur

import BlurView from 'react-native-blur';

...
<BlurView blurType="light" style={styles.blur}>
...