`fs.createReadStream()`

Creates a readable stream for incrementally reading a file.

Since Node 0.x Spec ↗

Syntax

fs.createReadStream(path[, options])

Parameters

Name	Type	Required	Description
`path`	`string \| Buffer \| URL`	Yes	The file to read.
`options`	`object \| string`	No	Encoding string, or object with `encoding`, `start`, `end`, `highWaterMark`, and `signal` for ranged or chunked reads.

Returns

fs.ReadStream — A Readable stream emitting data chunks.

Examples

import { createReadStream } from 'node:fs';

const stream = createReadStream('./big.log', 'utf8');
let lines = 0;
stream.on('data', (chunk) => {
  lines += chunk.split('\n').length - 1;
});
stream.on('end', () => console.log(lines, 'lines'));

Output

120000 lines

import { createReadStream } from 'node:fs';
import { createServer } from 'node:http';

createServer((req, res) => {
  createReadStream('./video.mp4').pipe(res);
}).listen(3000);

Notes

Streams keep memory flat regardless of file size, unlike `readFile`. Always handle the `'error'` event or pipe with `pipeline` so a read failure does not crash the process.