Need explanation of how local lambda run works


We have an object that we need to verify according to our rules and scheme, one of the property in the object contains array of similar by structure objects. To verify this section in for ... of loop it takes 30s, but if we will put each iteration into promises and run it as promise.All then runtime was reduce to 10s. I don't understand why it's happened, because we haven't inside verification any network requests or read/write from file system, it's just code and there are no any threads or something like this. Language: JS (NodeJS 18.x)

asked 8 months ago178 views
1 Answer

The significant reduction in runtime when using Promises and Promise.all for verification, even without network requests or file system operations, can be explained by how JavaScript handles asynchronous code and the event loop mechanism in Node.js.

Traditional for loops are control structures for synchronous iteration over data collections. However, they are ill-suited for handling asynchronous operations, as they can lead to callback loops and block the event loop, causing reduced application responsiveness. In contrast, Promises offer a structured, efficient approach to managing asynchronous tasks. They facilitate cleaner, error-handled, and modular code, mitigating callback loops. Promises also enable effective concurrency management by executing multiple asynchronous tasks in parallel, enhancing processing speed and efficiency in Node.js applications. Promises excel in handling I/O-bound operations, such as file I/O or network requests, making them a favored choice for contemporary asynchronous programming in JavaScript and Node.js, thereby improving code quality and maintainability.

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answered 8 months ago

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