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write - node__fs.d.ts - Node documentation
function write

Usage in Deno

```typescript import { write } from "node:node__fs.d.ts"; ```
write<TBuffer extends ArrayBufferView>(
fd: number,
buffer: TBuffer,
offset:
number
| undefined
| null
,
length:
number
| undefined
| null
,
position:
number
| undefined
| null
,
callback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void
,
): void
Write `buffer` to the file specified by `fd`. `offset` determines the part of the buffer to be written, and `length` is an integer specifying the number of bytes to write. `position` refers to the offset from the beginning of the file where this data should be written. If `typeof position !== 'number'`, the data will be written at the current position. See [`pwrite(2)`](http://man7.org/linux/man-pages/man2/pwrite.2.html). The callback will be given three arguments `(err, bytesWritten, buffer)` where `bytesWritten` specifies how many _bytes_ were written from `buffer`. If this method is invoked as its `util.promisify()` ed version, it returns a promise for an `Object` with `bytesWritten` and `buffer` properties. It is unsafe to use `fs.write()` multiple times on the same file without waiting for the callback. For this scenario, [createWriteStream](../.././node__fs.d.ts/~/createWriteStream) is recommended. On Linux, positional writes don't 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 ArrayBufferView

Parameters

fd: number
buffer: TBuffer
optional
offset:
number
| undefined
| null
= 0
optional
length:
number
| undefined
| null
= buffer.byteLength - offset
optional
position:
number
| undefined
| null
= 'null'
callback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void

Return Type

void
write<TBuffer extends ArrayBufferView>(
fd: number,
buffer: TBuffer,
offset:
number
| undefined
| null
,
length:
number
| undefined
| null
,
callback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void
,
): void
Asynchronously writes `buffer` to the file referenced by the supplied file descriptor.

Type Parameters

TBuffer extends ArrayBufferView

Parameters

fd: number
A file descriptor.
buffer: TBuffer
offset:
number
| undefined
| null
The part of the buffer to be written. If not supplied, defaults to `0`.
length:
number
| undefined
| null
The number of bytes to write. If not supplied, defaults to `buffer.length - offset`.
callback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void

Return Type

void
write<TBuffer extends ArrayBufferView>(
fd: number,
buffer: TBuffer,
offset:
number
| undefined
| null
,
callback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void
,
): void
Asynchronously writes `buffer` to the file referenced by the supplied file descriptor.

Type Parameters

TBuffer extends ArrayBufferView

Parameters

fd: number
A file descriptor.
buffer: TBuffer
offset:
number
| undefined
| null
The part of the buffer to be written. If not supplied, defaults to `0`.
callback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void

Return Type

void
write<TBuffer extends ArrayBufferView>(
fd: number,
buffer: TBuffer,
callback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void
,
): void
Asynchronously writes `buffer` to the file referenced by the supplied file descriptor.

Type Parameters

TBuffer extends ArrayBufferView

Parameters

fd: number
A file descriptor.
buffer: TBuffer
callback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void

Return Type

void
write(
fd: number,
string: string,
position:
number
| undefined
| null
,
encoding:
BufferEncoding
| undefined
| null
,
callback: (
err: ErrnoException | null,
written: number,
str: string,
) => void
,
): void
Asynchronously writes `string` to the file referenced by the supplied file descriptor.

Parameters

fd: number
A file descriptor.
string: string
A string to write.
position:
number
| undefined
| null
The offset from the beginning of the file where this data should be written. If not supplied, defaults to the current position.
encoding:
BufferEncoding
| undefined
| null
The expected string encoding.
callback: (
err: ErrnoException | null,
written: number,
str: string,
) => void

Return Type

void
write(
fd: number,
string: string,
position:
number
| undefined
| null
,
callback: (
err: ErrnoException | null,
written: number,
str: string,
) => void
,
): void
Asynchronously writes `string` to the file referenced by the supplied file descriptor.

Parameters

fd: number
A file descriptor.
string: string
A string to write.
position:
number
| undefined
| null
The offset from the beginning of the file where this data should be written. If not supplied, defaults to the current position.
callback: (
err: ErrnoException | null,
written: number,
str: string,
) => void

Return Type

void
write(
fd: number,
string: string,
callback: (
err: ErrnoException | null,
written: number,
str: string,
) => void
,
): void
Asynchronously writes `string` to the file referenced by the supplied file descriptor.

Parameters

fd: number
A file descriptor.
string: string
A string to write.
callback: (
err: ErrnoException | null,
written: number,
str: string,
) => void

Return Type

void