Guided Notes

Events & the EventEmitter

Event-driven programming in Node — EventEmitter, on/once/emit, passing data, removing listeners, and the error event.

Event-driven Node

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Much of Node is built on events: a server emits 'request', a stream emits 'data' and 'end', a process emits 'exit'. Your code registers listeners that run when events happen.

The events module's EventEmitter class lets you create your own event-driven objects: an order system that emits 'orderPlaced', a job queue that emits 'jobDone'.

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