Under the Hood of Asynchronous Execution
Explore the underlying mechanics of asynchronous execution in Node.js, focusing on the event loop, libuv, and callback handling.
We'll cover the following...
In previous lessons, we introduced asynchronous programming. Now, we’ll go under the hood to see how Node.js handles asynchronous tasks with the event loop, libuv, and the callback queue. Understanding these components helps us write efficient, non-blocking code.
Core components of asynchronous execution
When Node.js runs a file with both synchronous and asynchronous code, it coordinates execution using the following four components.:
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Call stack: The primary space where JavaScript code runs, handling synchronous tasks—such as variable declarations or
console.logstatements—immediately in the order they appear in the code. If a piece of code calls a function, that function is added to the top of the call stack. Once the function finishes executing, it is removed from the stack. For asynchronous functions likesetTimeout, Node.js initially adds them to the call stack, but instead of waiting there, they hand off control to libuv. -
libuv and Timer API: Node.js uses libuv, a library ...