How to Trim Specific Character from End of String in Javascript

In this tutorial, you will learn how to trim specific character from end of string in javascript. Even though most phrases only contain letters, they can also contain numbers and other characters. From a developer perspective, it can be a bit tricky to trim specific character from end of string.

There are numerous ways to trim specific character from end of string. A string consists of multiple characters and these characters in a string have a 0-based index. To get the rest of the string after the removal of the last character, we can make use of the substring() method. We can also use charAt() method to get the character by its index.

The length property of a string returns the number of total characters in that string. To get the index of the last letter in the string, we just need to subtract 1 from the length.

In the following example, we have one global variable that holds a string. Upon click of a button, we will trim specific character from end of 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 h1). The div element is just a wrapper for the rest of the elements.
  • The innerText for the button element is “Get” and for the h1 element, it is “Result”.
  • 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>Get</button>
    <h1>Result</h1>
  </div>

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

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

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

Javascript

  • We have selected the button element and h1 element using the document.querySelector() method and stored them in btnGet 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.
  • In the event handler function, we are getting the last character using charAt() method and storing it in the lastChar variable.
  • We are checking whether lastChar is equal to character "l".
  • In case the condition returns true, we are calling the substring() method and passing 2 parameters, the index of the last character and 0 which is the index of the first character. To get the index of the last character, we just need to subtract 1 from the string length. Finally, we will get a new string except for the last character.
  • In case the condition returns false, we are making no changes to the string.
  • The final string is stored in the result variable.
  • We are displaying the result in the h1 element using the innerText property.
let btnGet = document.querySelector("button");
let output = document.querySelector("h1");

let myString = "Its not funny at all";

btnGet.addEventListener("click", () => {  
  let lastChar = myString.charAt(myString.length - 1);
  let result = lastChar == 'l' ? myString.substring(myString.length - 1, 0) : myString;
  output.innerText = result;
});