So, the difference is not in exactly what the code you show achieves, but in how it is architected and thus how. These are treated as special cases within Node.js. If you don't know EventEmitter, you don't know Node. Also your knowledge of EventEmitter will greatly affect your efficiency as a Node.js developer, so make sure to read more about it and learn how it works inside out. This is used to make sure you aren't accidentally leaking event listeners. The use of the eventEmitter in example1 is very extensible and makes it easy to add future events to the object using the eventEmitter features or for outside agents to monitor or trigger events using a standardized interface. EventEmitter will help you write impressive event-based Node modules. NOTE: If you want to create more than 10 listeners on a single event, you will have to make a call to ee.setMaxListeners(n) where n is the max numbers of listeners (with zero being unlimited number of listeners).
So a simple example ran on the node REPL: var example_emitter = new (require('events').EventEmitter) Įxample_emitter.on("test", function () All the event emitting objects are instances of events.EventEmitter. Similarly, fs.readStream emits an event upon file opening.
For instance, whenever a peer user connects with net.Server, it emits an event. An event can be "emitted" (or in other words, the corresponding callback be called) multiple times or you can choose to only listen for the first time it is emitted. Event Emitter in Node JS E Nodes in Node JS emit many events regularly with the help of event emitter. In Node.js an event can be described simply as a string with a corresponding callback.
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