Confusion in event loop explanation of microtask queue

[iamharisai]

MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/HTML_DOM_API/Microtask_guide

What specific section or headline is this issue about?

https://arc.net/l/quote/iuxvdrho

What information was incorrect, unhelpful, or incomplete?

https://arc.net/l/quote/iuxvdrho This paragraph portraits that the oldest runnable task in the task queue will be executed first and then the microtasks in microtask queue will be executed in a single iteration of the event loop. Which is not true, as the microtask queue has priority.

What did you expect to see?

The mentioning of in a single iteration of the event loop, the microtasks queue will be executed first untill it is empty, and then the next iteration will look for empty call stack, then empty microtaskqueue then the oldest runnable task in the task queue will be executed.

Do you have any supporting links, references, or citations?

I am beginner in JS, so could be my fault to understand this.

Do you have anything more you want to share?

No response

MDN metadata

Page report details

• Folder: en-us/web/api/html_dom_api/microtask_guide
• MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/HTML_DOM_API/Microtask_guide
• GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/html_dom_api/microtask_guide/index.md
• Last commit: 5b20f5f
• Document last modified: 2024-12-19T15:37:45.000Z

[Josh-Cena]

Hi, our description is fully accurate. You can check https://html.spec.whatwg.org/multipage/webappapis.html#event-loop-processing-model. At every iteration of the event loop, we first process one task, then all microtasks, then paint the screen. Why? Because you can't have microtasks before you do at least one task. For example, the top-level code of <script> defines one task, and you have to execute that first.

[iamharisai]

Ah, you are right. Thank you so much for detailed explanation @Josh-Cena 🙏