June 25, 2020

How to Find Min and Max Value in Array in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to find min and max value in array in javascript. When we talk about the min and max values in the array that means we are looking for the lowest and highest values in the array.

If you are a newbie, then you might find it a bit tricky, but this problem can be easily solved using a Math object. It is one of the most useful built-in objects available in javascript because it contains certain useful properties and methods for mathematical constants and functions.

The Math object contains min() and max() methods that can be used to accomplish our goal. The point to be noted here is that both the methods take zero or more numbers as an argument and then after the comparison, they return min and max values.

In the following example, we have an array of numbers. Upon click of a button, we will find the min and max values in the array and display them on the screen. Please have a look over the code example and the steps given below.

HTML & CSS

We have 3 elements in the HTML file (div, button, and h1). The div element is just a wrapper for the rest of the elements.
The button element has “Get” and the h1 element has “Result” as innerText.
We have done some basic styling using CSS and added the link to our style.css stylesheet inside the head element.

We have also included our javascript file script.js with a script tag at the bottom.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <link rel="stylesheet" href="style.css">
    <title>Document</title>
</head>
<body>
    
    <div>
        <button>Get</button>
        <h1>Result</h1>
    </div>
    
    <script src="script.js"></script>
</body>
</html>

body {
    text-align: center;
}

div {
    display: inline-block;
}

button {
    display: inline-block;
    padding: 10px 20px;
}

Javascript

We have selected the button element and the h1 element using the document.querySelector() method and stored them in btnGet and result variables respectively.

We have global variable numbers which holds an array of numbers.
We have attached a click event listener to the button element.
In the event handler function, we are calling min() and max() methods of the Math object. We are using spread operator (…) to spread numbers array and passing that as an argument to these methods one by one. The returned values are stored in the min and max variables.

We are forming a string using min and max variables and displaying that in the h1 element using the innerText property.

let btnGet = document.querySelector('button');
let result = document.querySelector('h1');


let numbers = [21,30,56,7,10,98, 100];

btnGet.addEventListener('click', () => {
    let min = Math.min(...numbers);
    let max = Math.max(...numbers);

    result.innerText = `min: ${min} - max: ${max}`;
});

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