Homework Assignment #14: Callbacks and Promises

Objectives Create two different scripts. One will contain the callback-centered code, and the other the promises-centered code. The two scripts should contain the same functionality, and solve the same problems.

Calculate the square of num and log it to the console
Wait "num" milliseconds
Determine the prime-number that is closest to num without being greater than or equal to num, and then log it to the console
Determine the prime-number that is closest to numwithout being greater than or equal to num, and then log it to the console
Count the total elapsed time from when the original function was called until the last step was completed, and log that to the console as well.

Call Back Example

tt.innerHTML = "";
                         ran = number;ch = 0;
                         document.getElementById("input_ran").innerText = "";
                         calSquare(ran,squareRoot,findNearestPrime);
                     }
                     //for random number generation event
                     btn_ran.addEventListener("click",chi_ran);
                     function chi_ran(){

arr = [];
                         ran = Math.random()*1000;
                         ran = Math.floor(ran);ch = 0;
                         document.getElementById("input_ran").innerText = ran;
                         calSquare(ran,squareRoot,findNearestPrime);
                     }
                            ran = Math.random()*1000;
                            ran = Math.floor(ran);

//alert(ran);
                     // write down all console detail
                            function my(hh){
                                    let txt = "";
                                    let tt = document.getElementById("dis1");
                                    for (var i=0;i<hh.length;i++){

txt  = txt.concat(hh[i]) ;
                                    }

tt.innerHTML = txt;

}

callback(num);
                                callback1(num);

}
                     /*function chi(){
                         calSquare(ran,squareRoot,findNearestPrime);
                     }*/
                            function squareRoot(num) {
                                console.log(`Square root of ${num} is `  + Math.sqrt(num));
                                let tt3 = `Square root of ${num} is `  + Math.sqrt(num) + `<br>`;
                                arr.push(tt3);
                            }
                            function findNearestPrime(x){
                                let yy = x;
                                for (let i=x-1;i>0;i--){
                                   if (isPrime(i) === true){
                                       console.log("prime Number near " +  i);
                                       let tt4 = "prime Number near " +  i + `<br>`;
                                       arr.push(tt4);
                                       return i;
                                   }

}
                            }

function isPrime(num){
                                if (num < 2) return false;
                                 /**
                                 * An integer is prime if it is not divisible by any prime less than or equal to its square root
                                 **/
                                 let q = Math.floor(Math.sqrt(num));
                                for (let i=2;i<q;i++){
                                    if ( num%i===0 ){
                                        //console.log("find " + num + "and " + i );
                                        return false;
                                    }

}
                                return true;
                            }
                            //let xyz = isPrime(97);
                            //console.log(xyz);

console.log("/////////////// Callbacks ///////////////////////");
                            calSquare(ran,squareRoot,findNearestPrime);
                 </script>

Promise Example

tt.innerHTML = "";
                        ran1 = number;ch = 0;
                        document.getElementById("input_ran").innerText = "";
                        createPromise(ran1);
                    }
                    //Random generated number event
                    btn_ran.addEventListener("click",chi_ran);
                    function chi_ran(){

arr1 = [];
                        ran1 = Math.random()*1000;
                        ran1 = Math.floor(ran1);ch = 0;
                        document.getElementById("input_ran").innerText = ran1;
                        createPromise(ran1);
                    }

// write down all console detail
                    function my1(hh){
                       // let tt = document.getElementById("dis2");
                       // tt.innerHTML = hh;

let txt = "";
                        let tt = document.getElementById("dis2");
                        for (var i=0;i<hh.length;i++){

txt  = txt.concat(hh[i]) ;
                        }

tt.innerHTML = txt;
                    }
                    function findNearestPrime1(x){
                        let yy = x;
                        for (let i=x-1;i>0;i--){
                            if (isPrime1(i) === true){
                                console.log("prime Number near " +  i);
                                //let tt4 = "prime Number near " +  i + `<br>`;
                                //arr.push(tt4);
                                return i;
                            }

}
                    }
                    function isPrime1(num){
                        if (num < 2) return false;
                        /**
                         * An integer is prime if it is not divisible by any prime less than or equal to its square root
                         **/
                        let q = Math.floor(Math.sqrt(num));
                        for (let i=2;i<q;i++){
                            if ( num%i===0 ){
                                //console.log("find " + num + "and " + i );
                                return false;
                            }

}
                        return true;
                    }
                    var date1,date2;
                createPromise(ran1);
                function createPromise(num) {

date1 = new Date();
                    new Promise(function (resolve,reject) {

resolve (num);
                        console.log(`In Promise Square of ${num} is `+ num*num);
                        let hh1 = `In Promise Square of ${num} is `+ num*num + `<br>`;
                        arr1.push(hh1);
                        my1(arr1);

})
                        .then(function (num) {
                            setTimeout(function (num=ran1) {

console.log(`In Promise Square root of ${num} is ` + Math.sqrt(num));
                                let hh5 = `In Promise Square root of ${num} is ` + Math.sqrt(num) + `<br>`;
                                arr1.push(hh5);
                                my1(arr1);

let tt = findNearestPrime1(num);
                                console.log(`In Promise Nearest Prime number of ${num} is ` + tt);
                                let hh2 = `In Promise Nearest Prime number of ${num} is ` + tt + `<br>`;
                                arr1.push(hh2);
                                my1(arr1);

date2 = new Date();
                                let diff = date2 - date1;
                                console.log("time elapsed in promise "+ diff);

let hh3 = "time elapsed in promise "+ diff + "milliseconds \n";
                                arr1.push(hh3);

//if (ch === 0) {
                                    my1(arr1);ch = 1;
                                //}
                                return  Math.sqrt(num);

},num);

})
                        .catch(function (err) {
                            console.log("error is " + err);
                        });
                    }
                </script>