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TypeScript - get last n characters of string
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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:
- Using
substring()method, - Using
slice()method.
The below example shows how to use .substring() method to get the last n characters of the text string.
Runnable example:
xxxxxxxxxx1
const text: string = '12345';2
3
const n: number = 3;4
const substring: string = text.substring(text.length - n);5
6
console.log(substring); // 345Output:
xxxxxxxxxx1
345Another practical example:
xxxxxxxxxx1
const n = 3;2
3
console.log(''.substring(''.length - n) === ''); // true means string is empty4
console.log('1'.substring('1'.length - n)); // 15
console.log('12'.substring('12'.length - n)); // 126
console.log('123'.substring('123'.length - n)); // 1237
console.log('1234'.substring('1234'.length - n)); // 2348
console.log('12345'.substring('12345'.length - n)); // 345Output:
xxxxxxxxxx1
true2
13
124
1235
2346
345The below example shows the use of .slice() method with negative index to get the last n characters of the text string.
Runnable example:
xxxxxxxxxx1
const text: string = '12345';2
3
const n: number = 3;4
const substring: string = text.slice(-n);5
6
console.log(substring); // 345Output:
xxxxxxxxxx1
345In 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:
xxxxxxxxxx1
const n: number = 3;2
3
console.log(''.slice(-n) === ''); // true means string is empty4
console.log('1'.slice(-n)); // 15
console.log('12'.slice(-n)); // 126
console.log('123'.slice(-n)); // 1237
console.log('1234'.slice(-n)); // 2348
console.log('12345'.slice(-n)); // 345Output:
xxxxxxxxxx1
true2
13
124
1235
2346
345