How to Remove Extra Whitespace from a String in Javascript

In this tutorial, you will learn how to remove extra whitespace from a string in javascript. A sentence is formed with the help of multiple words and these words are separated from each other with the help of a space. By having a space, not only the words but the entire sentence becomes meaningful.

There are numerous ways to remove extra whitespace from a string. We are going to use the simplest approach which involves the usage of the regex pattern as well as replace() method. The replace() method searches the string for a particular value or a regex pattern and it returns a new string with the replaced values.

In the following example, we have one global variable that holds a string. Upon click of a button, we will remove extra whitespace from the string and display the result 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 pre). The div element is just a wrapper for the rest of the elements.
  • The innerText for the button element is “Replace”.
  • 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 class="container">    
    <button>Replace</button>
    <pre>Result</pre>
  </div>

  <script src="script.js"></script>
</body>

</html>
.container {        
    text-align: center;
}

button {
  margin-top: 10px;
  padding: 10px 20px;
}

pre {
  font-weight: bold;
  font-size: 30px;
}

Javascript

  • We have selected the button element and pre element using the document.querySelector() method and stored them in btnReplace and output variables respectively.
  • We have attached a click event listener to the button element.
  • We have a global variable myString which holds a string as its value.
  • We are displaying the original string in the pre element using the innerText property.
  • In the event handler function, we have regex variable that holds a regex pattern /\s+/g as its value.
  • We are calling replace() method and passing regex and single space as parameters. As a result, it will remove extra whitespace from the string. The new string returned by this method will be stored in the result variable.
  • We are displaying the result in the pre element using the innerText property.
let btnReplace = document.querySelector("button");
let output = document.querySelector("pre");

let myString = "John    my friend   is a good    doctor.";

output.innerText = myString;

btnReplace.addEventListener("click", () => {
  let regex = /\s+/g;
  let result = myString.replace(regex, " ");
  output.innerText = result;
});