promises.FileHandle.write - fs - Node

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;  }>