Exponentiation (**) Examples in JavaScript [Tutorial]

Introduction

Mathematics is everywhere within programming and languages like JavaScript, and its ability to carry out complex mathematical computations is one of the many reasons why we use them. Typical mathematical operations such as addition, subtraction, multiplication, and division are possible, but also, you can carry out other advanced mathematical operations in JavaScript such as exponentiation.

In this article, we will show how to execute exponentiation operations within JavaScript

 

What is Exponentiation in Mathematics?

Exponentiation is the process of raising a numerical quantity to the power of another where the numerical quantity is considered the base, and the other number is called the exponent (or power).

If the exponent is a positive integer, the exponentiation formula is defined as below

b^n = b * b *...* b * b (where the numbers of b is equal to n)
b^3 = b * b * b
b^5 = b * b * b * b * b

So, if you don’t know the exponentiation operator, your JavaScript code for the 4^3 might look like this.

let exp = 4 * 4 * 4;
console.log(exp);

Output

64

However, if we need to raise 4 to the power of 20, it will not make sense to type twenty 4. That’s where the exponentiation operator comes in. So to summarize, Exponentiation means raising a certain base number to the power of the exponent, for example, x^y. This can be read as x to the power of y. It means that we will multiply x by itself y number of times.

 

The Exponentiation operator (**) in JavaScript

The exponentiation operator - ** - allows us to raise the first operand to the power of the second operand and it supports BigInt type. In addition, the exponentiation operator is right-associative and so if there are more than one exponentiation, it executes the exponentiation operation from the right.

a * b * c = a * (b * c)

The ** operator holds a higher precedence over +, _, /, *. and therefore will become their operands.

Now, let’s see the ** operator in action

let exp = 4 ** 3;
console.log(exp);

Output

64

Also, the ** operator works BigInt values.

let exp = BigInt(345) ** BigInt(3);
console.log(exp);

Output

41063625n

Also, it works with floating-point numbers

let exp = 4 ** 3.3;
console.log(exp);

Output

97.00586025666546

However, you need to understand that especially with floating-point numbers, there is approximation going on and therefore will not be fully accurate.

If you want to make use of a negative number as your base, you will have to make use of a bracket to force the expression as it would throw an error - Unary operator used immediately before exponentiation expression. Parenthesis must be used to disambiguate operator precedence.

console.log((-2) ** 5);

Output

-32

 

Use pow method for exponentiation

Within the Math object, you can make use of the pow method to achieve exponentiation where it takes two arguments, the base number and the exponent.

Let’s take a look at some examples to see the pow method in action

console.log(Math.pow(4, 5));
console.log(Math.pow(6, -2));
console.log(Math.pow(-2, 5));

Output

1024
0.027777777777777776
-32

Unlike with the exponentiation operator, it doesn’t require you to force negative numbers with brackets. It’s similar to the ** operator, however, it only works with numbers and not BigInt types.

 

Summary

There are two ways to achieve exponentiation in JavaScript, the ** operator and the pow method. With the ** operator, you can work with both Numbers and BigInt values, however, with the pow method, you can only work with Numbers.

 

References

Exponentiation (**) - JavaScript | MDN (mozilla.org)
Exponentiation - Wikipedia
Operator precedence - JavaScript | MDN (mozilla.org)
Exponentiation (**) - JavaScript | MDN (mozilla.org)