TypeScript - get last n characters of string

In this article, we would like to show you how to get the last n characters of a string in TypeScript.

Below we present two solutions on how to do that: 

1. Using substring() method,
2. Using slice() method.

1. String substring() method example

The below example shows how to use .substring() method to get the last n characters of the text string. 

Runnable example:

const text: string = '12345';

const n: number = 3;
const substring: string = text.substring(text.length - n);

console.log(substring); // 345

Output:

345

Another practical example:

const n = 3;

console.log(''.substring(''.length - n) === ''); // true means string is empty
console.log('1'.substring('1'.length - n)); // 1
console.log('12'.substring('12'.length - n)); // 12
console.log('123'.substring('123'.length - n)); // 123
console.log('1234'.substring('1234'.length - n)); // 234
console.log('12345'.substring('12345'.length - n)); // 345

Output:

true
1
12
123
234
345

2. String slice() method example

The below example shows the use of .slice() method with negative index to get the last n characters of the text string.

Runnable example:

const text: string = '12345';

const n: number = 3;
const substring: string = text.slice(-n);

console.log(substring); // 345

Output:

345

In the second example, we can see that we can also use string slice() with negative indexes on a shorter or empty string which will give us the following results:

const n: number = 3;

console.log(''.slice(-n) === ''); // true means string is empty
console.log('1'.slice(-n)); // 1
console.log('12'.slice(-n)); // 12
console.log('123'.slice(-n)); // 123
console.log('1234'.slice(-n)); // 234
console.log('12345'.slice(-n)); // 345

Output:

true
1
12
123
234
345