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function write
#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).

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 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