JavaScript Finding the minimum or maximum element


Example

If your array or array-like object is numeric, that is, if all its elements are numbers, then you can use Math.min.apply or Math.max.apply by passing null as the first argument, and your array as the second.

var myArray = [1, 2, 3, 4];

Math.min.apply(null, myArray); // 1
Math.max.apply(null, myArray); // 4
6

In ES6 you can use the ... operator to spread an array and take the minimum or maximum element.

var myArray = [1, 2, 3, 4, 99, 20];

var maxValue = Math.max(...myArray); // 99
var minValue = Math.min(...myArray); // 1

The following example uses a for loop:

var maxValue = myArray[0];
for(var i = 1; i < myArray.length; i++) {
   var currentValue = myArray[i];
   if(currentValue > maxValue) {
      maxValue = currentValue;
   }
}
5.1

The following example uses Array.prototype.reduce() to find the minimum or maximum:

var myArray = [1, 2, 3, 4];

myArray.reduce(function(a, b) {
  return Math.min(a, b);
}); // 1

myArray.reduce(function(a, b) {
  return Math.max(a, b);
}); // 4
6

or using arrow functions:

myArray.reduce((a, b) => Math.min(a, b)); // 1
myArray.reduce((a, b) => Math.max(a, b)); // 4
5.1

To generalize the reduce version we'd have to pass in an initial value to cover the empty list case:

function myMax(array) {
  return array.reduce(function(maxSoFar, element) {
    return Math.max(maxSoFar, element);
  }, -Infinity);
}

myMax([3, 5]);             // 5
myMax([]);                 // -Infinity
Math.max.apply(null, []);  // -Infinity

For the details on how to properly use reduce see Reducing values.