fs.readSync does not validate invalid position type (accepts object instead of throwing) #62638

"use strict"
import fs from 'node:fs';
import os from 'node:os';
import path from 'node:path';

const memPath = fs.mkdtempSync(path.join(os.tmpdir(), 'node-temp-'));
const memFile = path.join(memPath, 'tempfile');
fs.writeFileSync(memFile, '');

// Open the file for reading and writing
const fd = fs.openSync(memFile, 'r+');

const ankor = new TextEncoder().encode('');

// This call is intentionally incorrect: `position` should be a number or null.
try {
  fs.readSync(fd, ankor, 0, ankor.length, { not: 'a number' } /* invalid position */);
  console.log('fs.readSync did not throw as expected');
} catch (err) {
  console.log('fs.readSync threw an error as expected:', err instanceof TypeError ? 'TypeError' : err.name, '-', err.message);
}

fs.closeSync(fd);