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Expo FileSystem (next) iconExpo FileSystem (next)

A library that provides access to the local file system on the device.

Android
iOS
tvOS
Bundled version:
~18.1.11
The next version of the FileSystem API is included in the expo-file-system library. It can be used alongside the previous API, and offers a simplified, object oriented way of performing filesystem operations.
To provide quicker updates, expo-file-system/next is currently unsupported in Expo Go and Snack. To use it, create a development build.

expo-file-system/next provides access to the file system stored locally on the device. It can also download files from the network.

Installation

Terminal
- npx expo install expo-file-system

If you are installing this in an existing React Native app, make sure to install expo in your project.

Usage

Writing and reading text files

example.ts
import { File, Paths } from 'expo-file-system/next';

try {
  const file = new File(Paths.cache, 'example.txt');
  file.create(); // can throw an error if the file already exists or no permission to create it
  file.write('Hello, world!');
  console.log(file.text()); // Hello, world!
} catch (error) {
  console.error(error);
}

Downloading files

Using downloadFileAsync:

example.ts
import { Directory, File, Paths } from 'expo-file-system/next';

const url = 'https://pdfobject.com/pdf/sample.pdf';
const destination = new Directory(Paths.cache, 'pdfs');
try {
  destination.create();
  const output = await File.downloadFileAsync(url, destination);
  console.log(output.exists); // true
  console.log(output.uri); // path to the downloaded file, e.g. '${cacheDirectory}/pdfs/sample.pdf'
} catch (error) {
  console.error(error);
}

Or using expo/fetch:

example.ts
import { fetch } from 'expo/fetch';
import { File, Paths } from 'expo-file-system/next';

const url = 'https://pdfobject.com/pdf/sample.pdf';
const response = await fetch(url);
const src = new File(Paths.cache, 'file.pdf');
src.write(await response.bytes());

Uploading files using expo/fetch

You can upload files as blobs directly with fetch built into the Expo package:

example.ts
import { fetch } from 'expo/fetch';
import { File, Paths } from 'expo-file-system';

const file = new File(Paths.cache, 'file.txt');
file.write('Hello, world!');

const response = await fetch('https://example.com', {
  method: 'POST',
  body: file,
});

Or using the FormData constructor:

example.ts
import { fetch } from 'expo/fetch';
import { File, Paths } from 'expo-file-system/next';

const src = new File(Paths.cache, 'file.txt');
file.write('Hello, world!');

const formData = new FormData();
formData.append('data', file);

const response = await fetch('https://example.com', {
  method: 'POST',
  body: formData,
});

Moving and copying files

example.ts
import { Directory, File, Paths } from 'expo-file-system/next';

try {
  const file = new File(Paths.document, 'example.txt');
  file.create();
  console.log(file.uri); // '${documentDirectory}/example.txt'
  const copiedFile = new File(Paths.cache, 'example-copy.txt');
  file.copy(copiedFile);
  console.log(copiedFile.uri); // '${cacheDirectory}/example-copy.txt'
  file.move(Paths.cache);
  console.log(file.uri); // '${cacheDirectory}/example.txt'
  file.move(new Directory(Paths.cache, 'newFolder'));
  console.log(file.uri); // '${cacheDirectory}/newFolder/example.txt'
} catch (error) {
  console.error(error);
}

Using legacy FileSystem API

example.ts
import * as FileSystem from 'expo-file-system';
import { File, Paths } from 'expo-file-system/next';

try {
  const file = new File(Paths.cache, 'example.txt');
  const content = await FileSystem.readAsStringAsync(file.uri);
  console.log(content);
} catch (error) {
  console.error(error);
}

Listing directory contents recursively

example.ts
import { Directory, Paths } from 'expo-file-system/next';

function printDirectory(directory: Directory, indent: number = 0) {
  console.log(`${' '.repeat(indent)} + ${directory.name}`);
  const contents = directory.list();
  for (const item of contents) {
    if (item instanceof Directory) {
      printDirectory(item, indent + 2);
    } else {
      console.log(`${' '.repeat(indent + 2)} - ${item.name} (${item.size} bytes)`);
    }
  }
}

try {
  printDirectory(new Directory(Paths.cache));
} catch (error) {
  console.error(error);
}

API

No API data file found, sorry!