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Apprendre EventEmitter Patterns and Best Practices | Advanced EventEmitters and Process Management
Node.js Events and Process Management

bookEventEmitter Patterns and Best Practices

When working with Node.js, mastering the use of EventEmitter is crucial for building robust and maintainable applications. You should always follow best practices for error handling, avoiding memory leaks, and implementing one-time listeners to ensure your event-driven code remains efficient and predictable.

A key practice is to handle errors explicitly. If an EventEmitter emits an 'error' event and there are no listeners for it, Node.js will throw and crash your process. Always add an error listener when you expect that failures might occur, such as in network operations or asynchronous file handling.

Memory leaks can occur if you add too many listeners to an emitter, especially if you forget to remove listeners that are no longer needed. Node.js will warn you if more than 10 listeners are added to a single event, but you should proactively manage listeners by removing them when they're no longer necessary. This is especially important in long-running applications or when creating and destroying many objects that emit events.

For events that should only be handled once—such as responding to a 'ready' or 'connected' event—use one-time listeners. This not only prevents accidental multiple executions but also helps with memory management by automatically removing the listener after it is invoked.

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Which of the following is an effective way to prevent memory leaks when using EventEmitters?

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Merci pour vos commentaires !

Section 2. Chapitre 1

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bookEventEmitter Patterns and Best Practices

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When working with Node.js, mastering the use of EventEmitter is crucial for building robust and maintainable applications. You should always follow best practices for error handling, avoiding memory leaks, and implementing one-time listeners to ensure your event-driven code remains efficient and predictable.

A key practice is to handle errors explicitly. If an EventEmitter emits an 'error' event and there are no listeners for it, Node.js will throw and crash your process. Always add an error listener when you expect that failures might occur, such as in network operations or asynchronous file handling.

Memory leaks can occur if you add too many listeners to an emitter, especially if you forget to remove listeners that are no longer needed. Node.js will warn you if more than 10 listeners are added to a single event, but you should proactively manage listeners by removing them when they're no longer necessary. This is especially important in long-running applications or when creating and destroying many objects that emit events.

For events that should only be handled once—such as responding to a 'ready' or 'connected' event—use one-time listeners. This not only prevents accidental multiple executions but also helps with memory management by automatically removing the listener after it is invoked.

index.js

index.js

copy
question mark

Which of the following is an effective way to prevent memory leaks when using EventEmitters?

Select the correct answer

Tout était clair ?

Comment pouvons-nous l'améliorer ?

Merci pour vos commentaires !

Section 2. Chapitre 1
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