second largest number in array javascript

1var secondMax = function (){ 
2    var arr = [20, 120, 111, 215, 54, 78]; // use int arrays
3    var max = Math.max.apply(null, arr); // get the max of the array
4    arr.splice(arr.indexOf(max), 1); // remove max from the array
5    return Math.max.apply(null, arr); // get the 2nd max
6};
7

1const max = arr => Math.max(...arr);

1var secondMax = function (arr){ 
2    var max = Math.max.apply(null, arr), // get the max of the array
3        maxi = arr.indexOf(max);
4    arr[maxi] = -Infinity; // replace max in the array with -infinity
5    var secondMax = Math.max.apply(null, arr); // get the new max 
6    arr[maxi] = max;
7    return secondMax;
8};

1var secondMax = function (){ 
2    var arr = [20, 120, 111, 215, 54, 78]; // use int arrays
3    var max = Math.max.apply(null, arr); // get the max of the array
4    arr.splice(arr.indexOf(max), 1); // remove max from the array
5    return Math.max.apply(null, arr); // get the 2nd max
6};

1['20','120','111','215','54','78'].sort(function(a, b) { return b - a; })[1];
2// '120'
3