JAVASCRIPT INTERVIEW QUESTION It looks like you're exploring the order of execution in JavaScript, specifically with regards to setTimeout, Promise.resolve, and synchronous code. `setTimeout(()=>{ console.log('Timeout') },0) Promise.resolve().then(()=> console.log('promise') ) console.log('end');` Here's what happens: setTimeout is called with a timeout of 0, which means the callback will be executed as soon as possible, but not immediately. It's added to the macrotask queue. Promise.resolve() creates a resolved promise, and the then method is called with a callback. This callback is added to the microtask queue. console.log('end') is executed immediately, as it's a synchronous statement. The order of execution is: 1. end 2. promise (microtask queue is executed before the next macrotask) 3. Timeout (macrotask queue is executed)
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` console.log('start'); setTimeout(() => { console.log("middle"); }, 0); console.log('end');` 1. console.log('start') is executed immediately. 2. setTimeout is called with a timeout of 0, which adds the callback to the macrotask queue. 3. console.log('end') is executed immediately. The order of execution is: start end middle (macrotask is executed) ############################################################################################ Think of it like this: Synchronous code console.log('start') console.log('end') Macrotask queue console.log("middle") The synchronous code is executed first, and then the macrotask queue is processed, executing the callback. key concept: synchronous and asynchronous code works- 1. synchronous code is executed first 2. macrotask queue is executed next 3. microtask queue is executed after the macrotask queue --> macrotask queue: the queue of tasks that are executed by the browser, such as setTimeout, setInterval, I/O, UI rendering, etc. --> microtask queue: the queue of tasks that are executed by the browser, such as promise resolution/rejection, async/await, etc.
