FileSystemSyncAccessHandle: truncate() method
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since March 2023.
Secure context: This feature is available only insecure contexts (HTTPS), in some or allsupporting browsers.
Note: This feature is only available inDedicated Web Workers.
Thetruncate() method of theFileSystemSyncAccessHandle interface resizes the file associated with the handle to a specified number of bytes.
Syntax
truncate(newSize)Parameters
newSizeThe number of bytes to resize the file to.
Return value
None (undefined).
Exceptions
InvalidStateErrorDOMExceptionThrown if the associated access handle is already closed, or if the modification of the file's binary data otherwise fails.
QuotaExceededErrorThrown if the
newSizeis larger than the original size of the file, and exceeds the browser'sstorage quota.TypeErrorThrown if the underlying file system does not support setting the file size to the new size.
Examples
async function truncateFile() { // Get handle to draft file const root = await navigator.storage.getDirectory(); const draftHandle = await root.getFileHandle("draft.txt", { create: true }); // Get sync access handle const accessHandle = await draftHandle.createSyncAccessHandle(); // Truncate the file to 0 bytes accessHandle.truncate(0); // Persist changes to disk. accessHandle.flush(); // Always close FileSystemSyncAccessHandle if done. accessHandle.close();}Specifications
| Specification |
|---|
| File System # api-filesystemsyncaccesshandle-truncate |