# Clamp or map a number to a range in JavaScript

Clamping a number means to restrict it to a certain range. Mapping a number to a range means to convert it from one range to another. Both operations are common in JavaScript and can be easily implemented using simple math.

## Clamp a number

In order to clamp a number, you can use `Math.max()`

and `Math.min()`

to find the **closest value** within the specified range.

const clampNumber = (num, a, b) => Math.max(Math.min(num, Math.max(a, b)), Math.min(a, b)); clampNumber(2, 3, 5); // 3 clampNumber(1, -1, -5); // -1

### Convert a number to a safe integer

A special case of clamping a number is converting it to a **safe integer**. You can use the `Number.MAX_SAFE_INTEGER`

and `Number.MIN_SAFE_INTEGER`

constants to find the closest safe value. Additionally, use `Math.round()`

to convert to an integer.

const toSafeInteger = num => Math.round( Math.max(Math.min(num, Number.MAX_SAFE_INTEGER), Number.MIN_SAFE_INTEGER) ); toSafeInteger('3.2'); // 3 toSafeInteger(Infinity); // 9007199254740991

## Map a number to a range

Mapping a number to a range is a simple **linear transformation**. Provided the original and the target range, you can map between the limits of the two ranges.

const mapNumRange = (num, inMin, inMax, outMin, outMax) => ((num - inMin) * (outMax - outMin)) / (inMax - inMin) + outMin; mapNumRange(5, 0, 10, 0, 100); // 50