Resolve a path as not found about memfs HOT 2 CLOSED

import fs from 'fs';
import { vol, fs as memfs } from 'memfs';
import { ufs } from 'unionfs';
import { spy } from 'spyfs';

vol.fromJSON({
  '/foo': 'bar',
});

ufs.use(fs).use(memfs);

const sfs = spy(ufs, ({ method, args, resolve, reject }) => {
  if (args[0] === '/foo') {
    if (method === 'existsSync') resolve(true);
    else reject(new Error("Can't touch this!"));
  }
});

console.log('existsSync:', sfs.existsSync('/foo'));
try {
  console.log('readFileSync:', sfs.readFileSync('/foo'));
} catch (e) {
  console.error('readFileSync error:', e.message);
}