JavaScript - max value in array

In this article, we would like to show you how to find maximum value in array in JavaScript.

Quick solution:

const numbers = [2, 3, 1]

const max = Math.max(...numbers)

console.log(max);  // 3

1. Math.max()

In this example, we use Math.max() method with the spread operator (...) to find the maximum value of the numbers array. 

// ONLINE-RUNNER:browser;

const numbers = [2, 3, 1]

const max = Math.max(...numbers)

console.log(max);  // 3

or:

// ONLINE-RUNNER:browser;

const array = [3, 1, 2];

const result = Math.max.apply(null, array);

console.log(result);  // 3

2. Using reduce() method

// ONLINE-RUNNER:browser;

const array = [3, 1, 2];

const result = array.reduce((a, b) => Math.min(a, b));

console.log(result);  // 1

3. By comparing items

// ONLINE-RUNNER:browser;

const array = [3, 1, 2];

let result = -Infinity;

for (const item of array) {
    if (item > result) {
        result = item;
    }
}

console.log(result); // 3

4. Add function to Array.prototype

In this example, we add a new function max() to the Array() object so we can use it on every array as it was a built-in function.

// ONLINE-RUNNER:browser;

var numbers = [2, 3, 1];

Array.prototype.max = function() {
    return Math.max.apply(null, this);
};

console.log(numbers.max()); // 3

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• JavaScript - how to add new function to array class / type