Fs Eisdir

fs — reading a directory as a file throws EISDIR.

fopen(2) on a directory succeeds on both Linux and macOS, then hands back garbage/zero bytes. Node instead throws EISDIR: illegal operation on a directory, read so readFileSync guards its read path with a stat(2) check up front: a directory path sets errno to EISDIR and surfaces as an ordinary catchable Error whose `.code` is the Node error-code name "EISDIR" — the same shape every other fs failure (ENOENT, EEXIST, ...) already uses.

import * as fs from 'fs';

fs.mkdirSync('/tmp/klain-eisdir-demo', { recursive: true });

try {
  const contents = fs.readFileSync('/tmp/klain-eisdir-demo');
  console.log('unexpected: read ' + contents.length + ' bytes');
} catch (e) {
  // .code is the canonical fs idiom — what real code branches on.
  console.log('code: ' + (e as any).code);
  console.log('is Error: ' + (e instanceof Error));
}

fs.rmdirSync('/tmp/klain-eisdir-demo');

View source on GitHubexamples/fs/fs_eisdir.ts

← Fs Async Pool Fs Link Types →