JavaScript - replace last character in string

In this article, we're going to have a look at how to replace the last character from the string in JavaScript.

1. String slice() method example

This approach allows getting substring by using negative indexes. So by using 0 and -1 indexes as the range we get <0, text.length - 1> text range. Then, we add the replacement at the end of the result string to replace the missing character.

// ONLINE-RUNNER:browser;

let text = 'ABC';
let replacement = 'x';
let result = text.slice(0, -1) + replacement;

console.log(result); // ABx

2. String substring() method example

This is an alternative approach to slice method based solution. We remove the last character to add the replacement at the end of the result string to replace the missing character.

// ONLINE-RUNNER:browser;

let text = 'ABC';
let replacement = 'x';
let result = text.substring(0, text.length - 1) + replacement;

console.log(result); // ABx

3. String replace() method example

There is another trick that allows replacing all characters that match expression conditions with an empty string. By using .$ pattern we match any character that is located at the end of the string.

// ONLINE-RUNNER:browser;

let text = 'ABC';
let replacement = 'x';
let result = text.replace(/.$/, replacement);

console.log(result); // ABx