JavaScript - 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 JavaScript.

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:

// ONLINE-RUNNER:browser;

var text = '12345';

var n = 3;
var substring = text.substring(text.length - n);

console.log(substring); // 345

Another practical example:

// ONLINE-RUNNER:browser;

var 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

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:

// ONLINE-RUNNER:browser;

var text = '12345';

var n = 3;
var substring = text.slice(-n);

console.log(substring); // 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:

// ONLINE-RUNNER:browser;

var n = 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

 References

• String.prototype.substring() - MDN Web Docs

• Array.prototype.slice() - MDN Web Docs