TypeScript - get first n characters of string

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

Example 1

The below example shows the use of .substring() method which returns the part of a string between the 0 and n indexes.

Runnable example:

const text: string = '12345';

const n: number = 3;
const substring: string = text.substring(0, n);

console.log('text: ' + text); // 12345
console.log('substring: ' + substring); // 123

Output:

text: 12345
substring: 123

Example 2

In the second example, we can see the result when we want to get a substring from a string in constious cases (like a string shorter than the number of characters we want to get or an empty string).

Runnable example:

// true means string is empty

console.log(''.substring(0, 3) === ''); // empty
console.log('1'.substring(0, 3)); // 1
console.log('12'.substring(0, 3)); // 12
console.log('123'.substring(0, 3)); // 123
console.log('1234'.substring(0, 3)); // 123
console.log('12345'.substring(0, 3)); // 123

Output:

true
1
12
123
123
123

Note:
Don't use substr() because it's a non-standard method.