Math.js is a great JavaScript library that makes it easy to work with units and unit conversions. It helps you define units, change between different units, and do math with them without any difficulties. In this article, we’ll learn how to manage units and do conversions using Math.js.

Run the below command before running the code in your local system:

npm i mathjs

These are the following types of conversion that we are going to discuss:

Basic Unit Conversion

It tells how to convert between different units using Math.js. It includes examples of converting measurements like length, weight, and time from one unit to another.

Example: By creating a unit object for 5 meters and converting it to centimeters using math.js, we can easily handle unit conversions and display the result.

// script.js

const math = require('mathjs');

// Convert 5 meters to centimeters
const value = math.unit(5, 'm');
const convertedValue = value.to('cm');

console.log(`5 meters is equal to ${convertedValue.toString()}`);

Output:

5 meters is equal to 500 cm

Arithmetic with Units

This explains how to perform arithmetic operations with units using Math.js. It covers how to add, subtract, multiply, and divide quantities with different units.

Example: By defining two unit objects (3 meters and 50 centimeters) and using the math.add function, we can correctly add the lengths together and display the total length.

const math = require('mathjs');

// Define the expression
const expression = '3x^2 + 2x + 1';

// Differentiate the expression with respect to x
const derivative = math.derivative(expression, 'x');

console.log(`The derivative of ${expression} 
              is ${derivative.toString()}`);

Output:

The total length is 3.5 m

Complex Unit Conversion

Here, Math.js is used to perform complex unit conversions. By defining a speed in kilometres per hour and converting it to meters per second using method, we can handle conversions between different units of measurement and display the converted speed.

Example: This illustrates the derivative of the expression ‘3x^2 + 2x + 1’ with respect to x using Math.js.

// Define the expression
const expression = '3x^2 + 2x + 1';

// Differentiate the expression with respect to x
const derivative = math.derivative(expression, 'x');

console.log(`The derivative of ${expression} is ${derivative.toString()}`);

Output:

90 km/h is equal to 25 m / s