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write

function write
Jump to headingwrite<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 Jump to heading

Jump to headingTBuffer extends ArrayBufferView

Parameters Jump to heading

optional
Jump to headingoffset:
number
| undefined
| null
 = 0
optional
Jump to headinglength:
number
| undefined
| null
 = buffer.byteLength - offset
optional
Jump to headingposition:
number
| undefined
| null
 = 'null'
Jump to headingcallback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void

Return Type Jump to heading

void
Jump to headingwrite<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 Jump to heading

Jump to headingTBuffer extends ArrayBufferView

Parameters Jump to heading

A file descriptor.

Jump to headingoffset:
number
| undefined
| null

The part of the buffer to be written. If not supplied, defaults to 0.

Jump to headinglength:
number
| undefined
| null

The number of bytes to write. If not supplied, defaults to buffer.length - offset.

Jump to headingcallback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void

Return Type Jump to heading

void
Jump to headingwrite<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 Jump to heading

Jump to headingTBuffer extends ArrayBufferView

Parameters Jump to heading

A file descriptor.

Jump to headingoffset:
number
| undefined
| null

The part of the buffer to be written. If not supplied, defaults to 0.

Jump to headingcallback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void

Return Type Jump to heading

void
Jump to headingwrite<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 Jump to heading

Jump to headingTBuffer extends ArrayBufferView

Parameters Jump to heading

A file descriptor.

Jump to headingcallback: (
err: ErrnoException | null,
written: number,
buffer: TBuffer,
) => void

Return Type Jump to heading

void
Jump to headingwrite(
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 Jump to heading

A file descriptor.

Jump to headingstring: string

A string to write.

Jump to headingposition:
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.

Jump to headingencoding:
BufferEncoding
| undefined
| null

The expected string encoding.

Jump to headingcallback: (
err: ErrnoException | null,
written: number,
str: string,
) => void

Return Type Jump to heading

void
Jump to headingwrite(
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 Jump to heading

A file descriptor.

Jump to headingstring: string

A string to write.

Jump to headingposition:
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.

Jump to headingcallback: (
err: ErrnoException | null,
written: number,
str: string,
) => void

Return Type Jump to heading

void
Jump to headingwrite(
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 Jump to heading

A file descriptor.

Jump to headingstring: string

A string to write.

Jump to headingcallback: (
err: ErrnoException | null,
written: number,
str: string,
) => void

Return Type Jump to heading

void
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