Expo 文件系统

Copies a directory.

Copies a directory synchronously.

Creates a directory that the current uri points to.

Deletes a directory. Also deletes all files and directories inside the directory.

Retrieves an object containing properties of a directory.

Lists the contents of a directory. Calling this method if the parent directory does not exist will throw an error.

Moves a directory. Updates the uri property that now points to the new location.

Moves a directory synchronously. Updates the uri property that now points to the new location.

Renames a directory.

Watches this directory for changes to its contents or the directory itself.

Events are emitted when files or subdirectories are created, modified, deleted, or renamed within this directory. On iOS, child changes are surfaced as a coarse-grained modified event on the directory itself, so filtering for child-level created, deleted, or renamed events is not reliable. The watcher automatically stops when the directory is deleted or renamed. To stop watching manually, call remove() on the returned subscription.

const cacheDir = new Directory(Paths.cache);
const subscription = cacheDir.watch((event) => {
  console.log(`${event.type}: ${event.target.uri}`);
});

// Later, stop watching:
subscription.remove();

Adds a listener for the given event name.

Synchronously calls all the listeners attached to that specific event. The event can include any number of arguments that will be passed to the listeners.

Returns a number of listeners added to the given event.

A function that detaches the JS and native objects to let the native object deallocate before the JS object gets deallocated by the JS garbage collector. Any subsequent calls to native functions of the object will throw an error as it is no longer associated with its native counterpart.

In most cases, you should never need to use this function, except some specific performance-critical cases when manual memory management makes sense and the native object is known to exclusively retain some native memory (such as binary data or image bitmap). Before calling this function, you should ensure that nothing else will use this object later on. Shared objects created by React hooks are usually automatically released in the effect's cleanup phase, for example: useVideoPlayer() from expo-video and useImage() from expo-image.

Removes all listeners for the given event name.

Removes a listener for the given event name.

Function that is automatically invoked when the first listener for an event with the given name is added. Override it in a subclass to perform some additional setup once the event started being observed.

Function that is automatically invoked when the last listener for an event with the given name is removed. Override it in a subclass to perform some additional cleanup once the event is no longer observed.

The arrayBuffer() method of the Blob interface returns a Promise that resolves with the contents of the blob as binary data contained in an ArrayBuffer.

MDN Reference

Retrieves content of the file as base64.

Retrieves content of the file as base64.

Retrieves byte content of the entire file.

Retrieves byte content of the entire file.

Copies a file.

Copies a file synchronously.

Creates a file.

Creates a download task for downloading a file with pause/resume support.

const dest = new File(Paths.document, 'video.mp4');
const downloadTask = File.createDownloadTask(url, dest, {
  onProgress: ({ bytesWritten, totalBytes }) => {
    console.log(`Downloaded ${bytesWritten} of ${totalBytes} bytes`);
  }
});
const file = await downloadTask.downloadAsync();

Creates an upload task for uploading this file with progress tracking.

const file = new File(Paths.document, 'photo.jpg');
const uploadTask = file.createUploadTask(url, {
  uploadType: UploadType.MULTIPART,
  headers: { Authorization: 'Bearer token' },
  onProgress: ({ bytesSent, totalBytes }) => {
    console.log(`Uploaded ${bytesSent} of ${totalBytes} bytes`);
  }
});
const result = await uploadTask.uploadAsync();
console.log('Upload status:', result.status);

Deletes a file.

Retrieves an object containing properties of a file

Moves a directory. Updates the uri property that now points to the new location.

Moves a file synchronously. Updates the uri property that now points to the new location.

Returns A FileHandle object that can be used to read and write data to the file.

An overload of the pickFileAsync method, which picks and returns a single File. This overload requires options to have multipleFiles flag be undefined or false.

An overload of the pickFileAsync method, which picks and returns a list of File's. This overload requires options to have multipleFiles flag be true.

A static method that opens a file picker to select a single file of specified type. On iOS, it returns a temporary copy of the file leaving the original file untouched.

Selecting multiple files is not supported yet.

Renames a file.

The slice() method of the Blob interface creates and returns a new Blob object which contains data from a subset of the blob on which it's called.

MDN Reference

The stream() method of the Blob interface returns a ReadableStream which upon reading returns the data contained within the Blob.

MDN Reference

Retrieves text from the file.

Retrieves text from the file.

Uploads this file to the network.

The promise resolves with the HTTP response metadata and body for any completed response, including non-2xx status codes. It rejects only for local file errors, transport failures, or cancellation.

Watches this file for changes on the filesystem.

The watcher automatically stops when the file is deleted or renamed. To stop watching manually, call remove() on the returned subscription.

const file = new File(Paths.cache, 'data.json');
const subscription = file.watch((event) => {
  console.log(`File ${event.type}`);
});

// Later, stop watching:
subscription.remove();

Writes content to the file.

Returns the base name of a path.

Returns the directory name of a path.

Returns the extension of a path.

Returns an object that indicates if the specified path represents a directory.

Checks if a path is absolute.

Joins path segments into a single path.

Normalizes a path.

Parses a path into its components.

Resolves a relative path to an absolute path.

Adds a listener for the given event name.

Synchronously calls all the listeners attached to that specific event. The event can include any number of arguments that will be passed to the listeners.

Returns a number of listeners added to the given event.

A function that detaches the JS and native objects to let the native object deallocate before the JS object gets deallocated by the JS garbage collector. Any subsequent calls to native functions of the object will throw an error as it is no longer associated with its native counterpart.

In most cases, you should never need to use this function, except some specific performance-critical cases when manual memory management makes sense and the native object is known to exclusively retain some native memory (such as binary data or image bitmap). Before calling this function, you should ensure that nothing else will use this object later on. Shared objects created by React hooks are usually automatically released in the effect's cleanup phase, for example: useVideoPlayer() from expo-video and useImage() from expo-image.

Removes all listeners for the given event name.

Removes a listener for the given event name.

Function that is automatically invoked when the first listener for an event with the given name is added. Override it in a subclass to perform some additional setup once the event started being observed.

Function that is automatically invoked when the last listener for an event with the given name is removed. Override it in a subclass to perform some additional cleanup once the event is no longer observed.

Closes the file handle. This allows the file to be deleted, moved or read by a different process. Subsequent calls to readBytes or writeBytes will throw an error.

Reads the specified amount of bytes from the file at the current offset. Max amount of bytes read at once is capped by ArrayBuffer max size (32 bit signed MAX_INT on Android and 64 bit on iOS), but you can read from a FileHandle multiple times.

Writes the specified bytes to the file at the current offset.