This script is from a Nodejs introducing book. This part is about the event loop of Javascript. const sleep_st = (t) => new Promise((r) => setTimeout(r, t)); const sleep_im = () => new Promise((r) => setImmediate(r)); (async () => {…
There are many ways I can think of asking this question. Let's say we have a single-core CPU on which the OS is running two processes. Process 1 is a Node application and process 2, we don't care about. Given…
Code: setTimeout(() => console.log("1"), 1000) const startTime = Date.now() while (Date.now() - startTime < 5000); setTimeout(() => console.log("2"), 0) setTimeout(() => console.log("3"), 0) The output of this sample is: 2 3 1 Why it works this way ? In this…
Trying to figure out why the output of the following code is the way it is console.log("Start"); setInterval(function() { console.log("setInterval"); }, 5000); let date = new Date(); while(new Date() - date <= 10000) {} console.log("End"); Actual Output Start .... 10…
I'm working on my navbar. I have a header with a component within called HeaderSearch. What I want is to run a function each time the user clicks outside of the HeaderSearch. And then add an animation to close it.…
I had been struggling with the doubt , since in the event loop job queue has more priority than callback queue i.e, promises have more priority than setTimeout, then what about : new Promise(resolve => setTimeout(resolve, 0, "Done!")).then((message) => console.log(message));…
micro task Queue consist of callbacks/resolved functions from fetch, async/await. but why its given more priority then callback queue because sync code is executed first and then afterward async function is executed then why/how microtask queue is given more priority…
I realized that I was confused with requestAnimationFrame, although some time ago I thought I understood how it works. So what is the essence of my problem: They say that requestAnimationFrame, namely its callback, will be called before the rendering…
In this code: setTimeout(() => console.log('C'), 100); setTimeout(() => console.log('D'), 0); someSynchronousTask() // Assume this takes ~500ms This will log D -> C, but why? Why wouldn't it log C -> D? As setTimeout for C is pushed to event…
Let us say we have the following async function - async function foo(x,y) { x = x+1 await fetch('some_url') y = y+1 } When the function foo encounters await, the execution of foo must be suspended and its context must…