Skip to main content
promises.FileHandle.write - Node documentation
method promises.FileHandle.write

Usage in Deno

import { type promises } from "node:fs";
FileHandle.write<TBuffer extends Uint8Array>(
buffer: TBuffer,
offset?: number | null,
length?: number | null,
position?: number | null,
): Promise<{ bytesWritten: number; buffer: TBuffer; }>

Write buffer to the file.

The promise is fulfilled with an object containing two properties:

It is unsafe to use filehandle.write() multiple times on the same file without waiting for the promise to be fulfilled (or rejected). For this scenario, use filehandle.createWriteStream().

On Linux, positional writes do not work when the file is opened in append mode. The kernel ignores the position argument and always appends the data to the end of the file.

Type Parameters

TBuffer extends Uint8Array

Parameters

buffer: TBuffer
optional
offset: number | null

The start position from within buffer where the data to write begins.

optional
length: number | null = buffer.byteLength - offset

The number of bytes from buffer to write.

optional
position: number | null = 'null'

The offset from the beginning of the file where the data from buffer should be written. If position is not a number, the data will be written at the current position. See the POSIX pwrite(2) documentation for more detail.

Return Type

Promise<{ bytesWritten: number; buffer: TBuffer; }>
FileHandle.write(
data: string,
position?: number | null,
encoding?: BufferEncoding | null,
): Promise<{ bytesWritten: number; buffer: string; }>

Parameters

data: string
optional
position: number | null
optional
encoding: BufferEncoding | null

Return Type

Promise<{ bytesWritten: number; buffer: string; }>