Samuel Attard
3c70ff8e2a
* workers only get Node integration when the frame creating them has it (main frame, or nodeIntegrationInSubFrames); previously any same-process subframe's workers got it whenever nodeIntegrationInWorker was set (feat_plumb_node_integration_in_worker_through_workersettings.patch) * the "DevTools extension" preload exception applies only to extension documents hosted inside the DevTools front-end, not to any chrome-extension:// frame; browser-side startup-data push matches * specs for worker gating; docs and breaking-changes entries
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Multithreading
With Web Workers, it is possible to run JavaScript in OS-level threads.
Multi-threaded Node.js
It is possible to use Node.js features in Electron's Web Workers, to do
so the nodeIntegrationInWorker option should be set to true in
webPreferences.
const win = new BrowserWindow({
webPreferences: {
nodeIntegrationInWorker: true
}
})
Workers created by an <iframe> only get Node.js integration when the frame
itself has it, i.e. when nodeIntegrationInSubFrames is also enabled.
The nodeIntegrationInWorker can be used independent of nodeIntegration, but
sandbox must not be set to true.
Note
This option is not available in
SharedWorkers orService Workers owing to incompatibilities in sandboxing policies.
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 none of Electron's
built-in modules can be used in a 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-threaded environment, using them in Web Workers will lead to crashes and memory corruptions.
Note that even if a native Node.js module is thread-safe it's still not safe to
load it in a Web Worker because the process.dlopen function 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')
}
const worker = new Worker('script.js')