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HTML

              
                
              
            
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CSS

              
                
              
            
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JS

              
                //Calling a function without await keyword
// Multiple Callback => Promise => async/await
// which means async/await used to Simply the Promise chains not replace of promise

//async keyword used before function declaration, it always return a promise
// await expression causes async function execution to pause until a promise is settled(fullfilled or rejected) 
const f2 = () => 1
console.log("Returning a value:", f2())


const f3 = async () => 1 
console.log("Returning a promise:", f3())

const fn = val => new Promise((resolve, reject) => {
  setTimeout(() => {
      return resolve(val)
  }, 1000)
})

/****************************************************************/

const f4 = async () => { 
    // return a promise in a time interval
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve(1)
        }, 2000)
    })
}

const fnWithoutawait = async () => {
    const output = f4()
    console.log("OutPut printed before the promise resolved: ", output)
}
fnWithoutawait()


//Calling a function with await keyword
const awaitfn = async () => {
    const output = await f4()
    console.log("OutPut Printed after promised resolved because of await: ", output)

    //To Simply this f4 will return a promise and did the same thing
    f4().then(console.log)
    
}
awaitfn()

/****************************************************************/


// In the promiseWay every then will wait for the resolve state of the promise
const promiseWay = async () => {
    //This promise chains runs ASynchronously
    fn(10).then(res => increment(res)).then(res => increment(res)).then(res => increment(res)).then(console.log)
  
    //This will running Synchronously
    console.log("is this really run in Asynchronous way? No ")
}
promiseWay()

const increment = async resValue => {
    return new Promise((resolve, reject) => {
        setTimeout(() => {
            resolve(resValue + 10)
        },1000)
    })
}

/****************************************************************/


// In the awaitWay every await will wait for the resolve state of the promise
const awaitWay = async () => {
    const v1 = await fn(10)
    const v2 = await increment(v1)
    const v3 = await increment(v2)
    const v4 = await increment(v3)
    console.log("Print the awaitWay value:", v4)
  
    //This will running ASynchronously
    console.log("is this really run in Asynchronous way? Yes ")
}
awaitWay()

              
            
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