JavaScript - Get the first digit of a number

In this tutorial, we will learn how to get the first of a number in JavaScript.

Getting the first digit of a number

To get the first digit of a number:

1. Convert the number to a string.

2. Call the charAt() method on it, by passing the first digit index 0.

3. It returns the character at that index.

Here is an example:

const id = 13456;
const firstDigit = String(id).charAt(0);

// converting string back to number
console.log(Number(firstDigit));

Output:

1

The charAt() method accepts the character index as an argument and return its value in the string.

Similarly, we can also use the square brackets notation [] in JavaScript to get the first digit of a number.

Here is an example:

const id = 13456;
const firstDigit = String(id)[0];

// converting string back to number
console.log(Number(firstDigit));

Output:

1