Skip to main content
createReadStream - node__fs.d.ts - Node documentation
function createReadStream

Usage in Deno

```typescript import { createReadStream } from "node:node__fs.d.ts"; ```
createReadStream(
path: PathLike,
options?: BufferEncoding | ReadStreamOptions,
): ReadStream
Unlike the 16 KiB default `highWaterMark` for a `stream.Readable`, the stream returned by this method has a default `highWaterMark` of 64 KiB. `options` can include `start` and `end` values to read a range of bytes from the file instead of the entire file. Both `start` and `end` are inclusive and start counting at 0, allowed values are in the \[0, [`Number.MAX_SAFE_INTEGER`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/MAX_SAFE_INTEGER)\] range. If `fd` is specified and `start` is omitted or `undefined`, `fs.createReadStream()` reads sequentially from the current file position. The `encoding` can be any one of those accepted by `Buffer`. If `fd` is specified, `ReadStream` will ignore the `path` argument and will use the specified file descriptor. This means that no `'open'` event will be emitted. `fd` should be blocking; non-blocking `fd`s should be passed to `net.Socket`. If `fd` points to a character device that only supports blocking reads (such as keyboard or sound card), read operations do not finish until data is available. This can prevent the process from exiting and the stream from closing naturally. By default, the stream will emit a `'close'` event after it has been destroyed. Set the `emitClose` option to `false` to change this behavior. By providing the `fs` option, it is possible to override the corresponding `fs` implementations for `open`, `read`, and `close`. When providing the `fs` option, an override for `read` is required. If no `fd` is provided, an override for `open` is also required. If `autoClose` is `true`, an override for `close` is also required. ```js import { createReadStream } from 'node:fs'; // Create a stream from some character device. const stream = createReadStream('/dev/input/event0'); setTimeout(() => { stream.close(); // This may not close the stream. // Artificially marking end-of-stream, as if the underlying resource had // indicated end-of-file by itself, allows the stream to close. // This does not cancel pending read operations, and if there is such an // operation, the process may still not be able to exit successfully // until it finishes. stream.push(null); stream.read(0); }, 100); ``` If `autoClose` is false, then the file descriptor won't be closed, even if there's an error. It is the application's responsibility to close it and make sure there's no file descriptor leak. If `autoClose` is set to true (default behavior), on `'error'` or `'end'` the file descriptor will be closed automatically. `mode` sets the file mode (permission and sticky bits), but only if the file was created. An example to read the last 10 bytes of a file which is 100 bytes long: ```js import { createReadStream } from 'node:fs'; createReadStream('sample.txt', { start: 90, end: 99 }); ``` If `options` is a string, then it specifies the encoding.

Parameters

path: PathLike
optional
options: BufferEncoding | ReadStreamOptions

Return Type