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# WritableStreamDefaultWriter.write()

The **`write()`** method of the
`WritableStreamDefaultWriter` interface writes a passed chunk of data to a
`WritableStream` and its underlying sink, then returns a
`Promise` that resolves to indicate the success or failure of the write
operation.

Note that what "success" means is up to the underlying sink; it might indicate that the
chunk has been accepted, and not necessarily that it is safely saved to its ultimate
destination.

## Syntax

```js
write(chunk)
```

### Parameters

- `chunk`
  - : A block of binary data to pass to the `WritableStream`.

### Return value

A `Promise`, which fulfills with the `undefined` upon a
successful write, or rejects if the write fails or stream becomes errored before the
writing process is initiated.

### Exceptions

- `TypeError`
  - : The target stream is not a writable stream, or it does not have an owner.
