Javascript/CallBack_Hell.js at main · Anilnayak126/Javascript · GitHub

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// Callback Hell = situation in  java script where callbacks
//                 are nested inside other callbacks to  the
//                 degree where the code is difficult to  read
//                 old  pattern to  handle asynchronous fucntions .

//                 use promises + asynchronous  + async / await to avoid callback hell.


function task1(callback){
    setTimeout(() => {
        console.log('ts1 is completed.');
        callback();

    }, 2000);
}


function task2(callback){
    setTimeout(()=>{
        console.log(`Task2 is completed.`);
        callback()

    },1000)

}

function task3(callback){
    setTimeout(() => {
        console.log('task3 is completed.') ;
        callback()
    }, 3000);
}

function task4(callback){
    setTimeout(()=>{

        console.log(`task4 is completed .`);
        callback()
    },4000)
}
function task5(callback){
    setTimeout(()=>{

        console.log(`task5 is completed .`);
        callback()
    },6000)
}


task1(()=>{
    task2(() =>{
        task3(() => {
            task4(()=>{
                task5(()=> console.log(`All task completed`));
            });
        });
    });
});