TypeScript - replace last n characters in string

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

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

xxxxxxxxxx

const text: string = 'ABCD';

const n: number = 3;

const replacement: string = 'xyz';

const result: string = text.slice(0, -n) + replacement;

​

console.log(result); // Axyz

Output:

xxxxxxxxxx

Axyz

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

xxxxxxxxxx

const text: string = 'ABCD';

const n: number = 3;

const replacement: string = 'xyz';

const result: string = text.substring(0, text.length - n) + replacement;

​

console.log(result); // Axyz

Output:

xxxxxxxxxx

Axyz

1. TypeScript - replace last character in string

2. TypeScript - replace last 2 characters in string

3. TypeScript - replace last 3 characters in string

4. TypeScript - replace last 4 characters in string