Get the First 2 Digits of a Number in JavaScript

Sat Oct 23 20212 min read

Photo by Frank Mckenna

Get the First 2 Digits of a Number#

To get the first 2 digits of a number convert the number to a string and call the `slice()` method to get the first 2 characters. Then convert the string back to a number to get the first 2 digits.

index.js
```Copied!```const num = 1357;
const first2Str = String(num).slice(0, 2); // ๐๏ธ '13'
const first2Num = Number(first2Str); // ๐๏ธ 13
``````

The first step is to use the `String` object to convert the number to a string, so we can call the String.slice method on it.

The first parameter we pass to the `String.slice` method is the `start index` - the index at which we begin extraction of characters.

The second parameter is the `end index` - extract characters up to this index, but not including.

We start extracting characters at index `0` and go up to but not including index `2`.

Indexes are zero-based in JavaScript. The index of the first character in a string is `0` and the last - `str.length - 1`.
Even if the `end index` you provide to the `String.slice` method is greater than the string's length, the method does not throw an error, instead it returns a copy of the entire string.
index.js
```Copied!```const num = 1;

const first2Str = String(num).slice(0, 2); // ๐๏ธ '1'
const first2Num = Number(first2Str); // ๐๏ธ 1
``````

The `slice` method returns a string, so the last step is to convert it back to a number and we have the first 2 digits of the number.