January 31, 2022

How to Delete Last Letter of a String in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to delete last letter of a string in javascript. In the English alphabet, we have letters from A to Z. Depending upon the position of the word in a sentence, the last character can be a letter, number, or special character. This means the job here is to find the last letter and then delete it.

There are numerous ways to delete the last letter of a string. We are going to create custom function which involves usage of match() and lastIndexOf() methods to find the index of last letter in the string. Later, we will use slice() method to get rid of last letter.

In the following example, we have one global variable that holds a string. Upon click of a button, we will delete the last letter of 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 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 calling the removeLastLetter() method and passing myString as a parameter. This method will be responsible for removing first letter and returning rest of the string.
In removeLastLetter() method, we are finding all letters in the string using match() method which takes /[a-zA-Z]/g as a regex pattern. As a result, we are getting an array of letters which we are storing in the letters variable.
We are returning the string as it is if there are no letters in it.
Further, we are calling the slice() method and passing it -1 as a parameter which is the index of the last letter. As a result, we are getting the last letter and we are storing that in the letter variable.
We are using lastIndexOf() method to get the index of last letter in the string.
We are using slice() method to break the string into two parts based on the index number. These two parts are stored in the firstHalf and secondHalf variables.
We are joining both the parts using addition operator (+) and returning it as a single string.
The returned string is stored in the result variable and 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 = "Hello world 123";

btnGet.addEventListener("click", () => {
  let result = removeLastLetter(myString);
  output.innerText = result;
});

function removeLastLetter(str) {
  let letters = str.match(/[a-zA-Z]/g);
  if (!letters) return str;
  let letter = letters.slice(-1);
  let letterIndex = str.lastIndexOf(letter);
  let firstHalf = str.slice(0, letterIndex);
  let secondHalf = str.slice(letterIndex + 1);
  return firstHalf + secondHalf;
}

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