electron/docs/tutorial/multithreading.md

Multithreading

With Web Workers, it is possible to run JavaScript in OS-level threads.

Multi-threaded Node.js

In Electron, it is supported to use Node.js integration in Web Workers. To do so the nodeIntegrationInWorker option should be set to true in webPreferences.

let win = new BrowserWindow({
  webPreferences: {
    nodeIntegrationInWorker: true
  }
})

The nodeIntegrationInWorker can be used independent of nodeIntegration, but sandbox must not be set to true.

Available APIs

All built-in modules of Node.js are supported in Web Workers, and asar archives can still be read with Node.js APIs. However non of Electron's built-in modules can be used in multi-threaded environment.

Native Node.js modules

Any native Node.js module can be loaded directly in Web Workers, but it is strongly recommended not to do so. Most existing native modules have been written assuming single-thread environment, using them in a Web Workers will lead to crashes and memory corruptions.

Even when using a thread-safe native Node.js module, it should be noticed that the process.dlopen function is not thread safe, so loading a native module in Web Workers is not thread safe.

The only way to load a native module safely for now, is to make sure the app loads no native modules after the Web Workers get started.

process.dlopen = () => {
  throw new Error('Load native module is not safe')
}
new Worker('script.js')