What is event-loop-spinner?
The event-loop-spinner npm package is designed to help developers manage and monitor the event loop in Node.js applications. It provides utilities to prevent the event loop from being blocked by long-running synchronous code, ensuring that the application remains responsive.
What are event-loop-spinner's main functionalities?
Check if the event loop is blocked
This feature allows you to check if the event loop is currently blocked. It can be useful for monitoring the performance of your application and ensuring that it remains responsive.
const { isEventLoopBlocked } = require('event-loop-spinner');
if (isEventLoopBlocked()) {
console.log('The event loop is currently blocked.');
} else {
console.log('The event loop is running smoothly.');
}
Spin the event loop
This feature allows you to yield control to the event loop during long-running synchronous tasks. By calling `spin()`, you can ensure that the event loop remains responsive and can handle other tasks while your long-running task is in progress.
const { spin } = require('event-loop-spinner');
async function longRunningTask() {
for (let i = 0; i < 1000000; i++) {
// Simulate a long-running task
if (i % 1000 === 0) {
await spin(); // Yield control to the event loop
}
}
console.log('Task completed');
}
longRunningTask();
Other packages similar to event-loop-spinner
deasync
The deasync package allows you to turn asynchronous functions into synchronous ones. It can be used to prevent the event loop from being blocked by asynchronous operations. However, unlike event-loop-spinner, deasync focuses on converting async functions to sync rather than managing the event loop directly.
blocking-proxy
The blocking-proxy package is used to manage and control the event loop in end-to-end testing scenarios. It ensures that the event loop is not blocked by long-running tasks during tests. While it shares some similarities with event-loop-spinner, it is more specialized for testing environments.
async-hook
The async-hook package provides a way to track asynchronous resources in Node.js. It can be used to monitor the event loop and detect when it is blocked. However, it is more focused on tracking async resources rather than providing utilities to manage the event loop like event-loop-spinner.
event-loop-spinner
Tiny helper to prevent blocking Node.js event loop.
Example
import { eventLoopSpinner } from 'event-loop-spinner';
async function cpuIntensiveOperationHandler(hugeArray) {
for (const item of hugeArray) {
if (eventLoopSpinner.isStarving()) {
await eventLoopSpinner.spin();
}
}
}
Reading
Node.js: How even quick async functions can block the Event-Loop, starve I/O