This is a TypeScript wrapper of JS random-access-file library that wraps its callback-based API in Promises.
import {RandomAccessFile} from 'random-access-file-promises';
const file = new RandomAccessFile('path/to/file');
try {
const buffer = await file.read(42, 10);
console.log(buffer);
await file.write(42, Buffer.from('Hello, world!'));
} finally {
await file.close();
}
For convenience, there is also a withFile
function that automatically closes the file when the callback returns:
import {withFile} from 'random-access-file-promises';
await withFile('path/to/file', async (file) => {
const buffer = await file.read(42, 10);
console.log(buffer);
await file.write(42, Buffer.from('Hello, world!'));
});
Creates a new instance of RandomAccessFile
class.
Reads size
bytes from the file at the given offset
.
Writes buffer
to the file at the given offset
.
Returns the file stats, currently only size
is supported.
Truncates the file to the given length
.
Deletes length
bytes from the file at the given offset
.
Closes the file.
Unlinks the file, removes the directories up to opts.directory
if opts.rmdir
is set to true
Creates a new Pool
instance of size maxSize
.
withFile(path: string, callback: (file: RandomAccessFile) => Promise<void>, opts?: RandomAccessFileOptions): Promise<void>
Opens the file, calls the callback with the file instance and closes the file when the callback returns or errors out.
Options for RandomAccessFile
class.
Initial size of the file.
Specifies if the file should be truncated if opts.size
is not provided.
Directory to resolve the file in. Also acts as root directory if opts.rmdir
is set to true
.
Specifies if the file should be opened in read mode.
Both readable
and writable
set to true
results in RW
mode.
Both readable
and writable
set to false
results in W
mode.
Specifies if the file should be opened in write mode.
Both readable
and writable
set to true
results in RW
mode.
Both readable
and writable
set to false
results in W
mode.
Specify the pool to which this file belongs. Pool cam be created with createPool
function.
Specifies if the directory should be removed when the file is unlinked.
Specifies if a process-level lock should be acquired on the file. Files open in readonly mode provide a shared
flag to flock
.
Specifies if the file should be marked as a sparse file. May be required for del
operation.
Buffer allocation function.Buffer.allocUnsafe
is used by default.