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Er. Bhupendra Kumar
Er. Bhupendra Kumar

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MOST IMPORTANT JS OUTPUT BASED QUESTION:

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.
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