A Image Caching component that I use in react-native show a thumbnail while image is being loaded and also download it to device to allow quick loading the next time

CachedImage.js

import React, {useState, useEffect} from 'react';
import {
  Image,
  View,
  StyleSheet,
} from 'react-native';

import RNFetchBlob from 'rn-fetch-blob';
import isEmpty from '../../utils/is-empty';
import shorthash from 'shorthash';

const ProgressiveImage = props => {
 
  const {thumbnailSource, source, style} = props;

  const [imageUri, setImageUri] = useState(props.source.uri);

  //Make an async useEffect (Picked from SO. Don't trust this code :p)
  const useEffectAsync = (effect, inputs) => {
    useEffect(() => {
      effect();
    }, inputs);
  };

  useEffectAsync(async () => {
    if (!isEmpty(imageUri)) {
      const uri = await downloadImage(imageUri);
      setImageUri(uri);
    }
  }, []);

 

  return (
    <View style={styles.container}>
      <Image
        {...props}
        source={thumbnailSource}
        style={style}
        blurRadius={2}
      />
      
      <Image
        {...props}
        source={{uri: imageUri}}
        style={[styles.imageOverlay, style]}
      />
    </View>
  );
};

const downloadImage = async imageUrl => {
  
  let filename = `image-cache-${shorthash.unique(imageUrl)}`;
  let path = RNFetchBlob.fs.dirs.DocumentDir + '/' + filename;
  
  console.log('Checking if Image exists.....');
  let uriToReturn = null;
  try {
    const exist = await RNFetchBlob.fs.exists(path);
    console.log(`file ${exist ? '' : ' does not'} exist - ${path}`);
    if (exist) uriToReturn = 'file://' + path;
    else if (!exist) {
      console.log('Downloading Image.....');
      const res = await RNFetchBlob.config({
        fileCache: true,
        path,
      }).fetch('GET', imageUrl, {});
      uriToReturn = 'file://' + res.path();
    }
  } catch (err) {
    console.log(err);
  }

  return uriToReturn;
};

const styles = StyleSheet.create({
  imageOverlay: {
    position: 'absolute',
    left: 0,
    right: 0,
    bottom: 0,
    top: 0,
  },
  container: {
    // backgroundColor: '#e1e4e8',
  },
});

export default ProgressiveImage;

is-empty.js

const isEmpty = value => {
  return (
    value === null ||
    value === undefined ||
    (typeof value === 'object' && Object.keys(value).length === 0) ||
    (typeof value === 'string' && value.trim().length === 0)
  );
};

export default isEmpty;

Hello, I am new in react native how can I use your code can you please guide me where do I put these file?

Sure, so when instead of using Image component in react-native like this,

<Image source={'<image-url>'} />

You can use CachedImage,

import CachedImage from "<path-to-file-where-you-place-CachedImage-component>"

<CachedImage source={'<image-url>'} />

@Shivendra30 Thank you for your response I tried as you suggested but I am getting the error Unable to resolve module shorthash from shorthash could not be found within the project.

Any suggestion?

@Shivendra30 I am able to fix this however I tried this on simulator but images are not loading.

Any suggestion?

Yeah sure.
shorthash is a module that you need to install

So just do npm install shorthash in your project directory

@Shivendra30 I am able to fix this however I tried this on simulator but images are not loading.

Any suggestion?

@Shivendra30 I see that image is downloading but not display on app

@Shivendra30 any idea?

@vikashth1 Sorry for the delayed response.

Well, are you trying to load local images by any chance? Or from a remote URL?

Can you help me with some more data? Screenshots, logs, etc?

@Shivendra30 Thank you so much for your response.

I am trying to load images from URL.

It's downloading the image but not displaying in the app just blank.

Do let me know if you need anything else.

Can you reproduce on CodePen?

@Shivendra30 I am not familiar with CodePen?

https://codepen.io/ - You can write your code here by choosing a react native environment. You can watch some YT videos to figure this out. Super easy

Once you do that, we can work on the same code.