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Worker

Enhanced Worker implementation that extends Node.js worker_threads.Worker. This class adds environment variable sharing across different Node.js runtime environments, exit event fallback for environments where worker exit events aren't natively supported, and better cross-runtime compatibility (Node.js, Deno, Bun).

// Create a worker with exit fallback for compatibility
const worker = new Worker('./worker-script.js', {
  exitFallback: true,
  workerData: { inputData: [1, 2, 3] }
});

// Listen for messages
worker.on('message', (result) => {
  console.log('Worker result:', result);
});

// Listen for exit (works consistently across environments)
worker.on('exit', (code) => {
  console.log(`Worker exited with code ${code}`);
});

Types​

ThreadWorkerOptions​

Extended options for creating a Worker instance.

type ThreadWorkerOptions = WorkerOptions & {
  file?: string | URL;     // Path to the worker script file
  meta?: any;              // Optional metadata to associate with the worker
  exitFallback?: boolean;  // Whether to use message-based exit fallback
};

Methods​

constructor​

Creates a new Worker instance.

constructor(filename: string | URL, options?: WorkerOptions)

Parameters​

  • filename: Path to the worker script file
  • options: (Optional) Worker options

Examples​

// With default options
const worker = new Worker('./worker.js')

// With environment sharing and worker data
const worker = new Worker('./worker.js', {
  workerData: { config: { maxItems: 100 } },
  env: SHARE_ENV,
})

// With exit fallback for cross-runtime compatibility
const worker = new Worker('./worker.js', {
  exitFallback: true,
  workerData: { inputData: [1, 2, 3] },
})

on​

Adds an event listener for the specified event. The listener persists until removed.

on(event: string, listener: EventListener): this

Parameters​

  • event: Event name
  • listener: Event listener function

Returns​

  • This instance for chaining

once​

Adds a one-time event listener for the specified event. The listener is removed after being invoked once.

once(event: string, listener: EventListener): this

Parameters​

  • event: Event name
  • listener: Event listener function

Returns​

  • This instance for chaining

off​

Removes an event listener for the specified event.

off(event: string, listener: EventListener): this

Parameters​

  • event: Event name
  • listener: Event listener function to remove

Returns​

  • This instance for chaining

Events​

The Worker class emits several events that you can listen for:

message​

Emitted when the worker sends a message to the parent thread

messageerror​

Emitted when message deserialization fails

error​

Emitted when the worker throws an uncaught exception

exit​

Emitted when the worker exits (with exitCode)