largest no in array (js program)

Question

Return Largest Numbers in Arrays

//my code
function largestOfFour(arr) {

    var largest=[];    

    for(var i = 0; i < arr.length; i++){ 
        for (var j = 0; j < arr[i].length; j++) {
            if(arr[i][j] > largest){
                largest[i]= arr[i][j];

            }


        }

    }
   return largest;
}

largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);

//exp o/p

[27,5,39,1001]

//i m getting

[5,13]

Answer 1

if(arr[i][j]>largest) 

should be

if(arr[i][j]>largest[i])

Initialize your array too with some MIN value like 0

function largestOfFour(arr) {

var largest=[];    

for(var i = 0; i < arr.length; i++){ 
    largest[i] = 0;
    for (var j = 0; j < arr[i].length; j++) {
        if(arr[i][j] > largest[i]){
            largest[i]= arr[i][j];

        }


    }

}
  return largest;
}

Answer 2

I would do it in this way.

var largest=[];    

a = [[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]

for(var i = 0; i < a.length; i++){ 
largest.push(a[i].sort(function(a, b){return b-a})[0])
}
console.log(largest);