https://takao.blog/en/tags/event-loop/Recent content in Event-Loop on Commentary of TakaoHugo -- gohugo.ioenCommentary of TakaoSat, 13 Jun 2026 23:11:50 +0900https://takao.blog/en/web/js-event-loop/Mon, 19 Feb 2024 00:00:00 +0900https://takao.blog/en/web/js-event-loop/<img src="https://takao.blog/img/thumnail.webp" alt="Featured image of post JavaScript Event Loop Deep Dive: Microtasks, Macrotasks, and Beyond" /><p>The JavaScript event loop is one of the most important yet misunderstood concepts in the language. Despite JavaScript being single-threaded, its event loop enables non-blocking concurrency through a sophisticated queue system. This article builds a complete mental model of how JavaScript handles asynchronous execution, from the call stack to the microtask queue and everything in between.</p> <h2 id="the-call-stack-and-execution-model">The Call Stack and Execution Model </h2><p>JavaScript uses a call stack with a LIFO (Last In, First Out) structure. When a function is called, a new stack frame is pushed onto the stack. When the function returns, the frame is popped off. The key principle is run-to-completion: each function runs to completion before any other code can interrupt it.</p>