VirtualProvider

The base class for all VFS providers. Subclasses implement the essential primitives (such as open, stat, readdir, mkdir, rmdir, unlink, rename, etc.) and inherit default implementations of the derived methods (such as readFile, writeFile, exists, copyFile, access, etc.).

const { VirtualProvider } = require('node:vfs');

class StaticProvider extends VirtualProvider {
  get readonly() { return true; }

  statSync(path) { /* ... */ }
  openSync(path, flags) { /* ... */ }
  readdirSync(path, options) { /* ... */ }
  // ...
}

The base class throws ERR_METHOD_NOT_IMPLEMENTED for any primitive that has not been overridden, and rejects writes from a readonly provider with EROFS.