JavaScript Exponentiation Operator : A Complete Tutorial with Examples

The exponentiation operator (**) in JavaScript is used to raise a number (the base) to the power of another number (the exponent).

This operator was introduced in ECMAScript 2016 (ES7) and provides a more concise and readable way to perform power operations compared to the Math.pow() method.

Syntax

let result = base ** exponent;

base: The number you want to raise.
exponent: The power to which you want to raise the base.

Examples

1. Basic Exponentiation

let base = 5;
let exponent = 3;
let result = base ** exponent;

console.log(result); // Output: 125

Explanation

Here, 5 ** 3 means 5 raised to the power of 3 (5 * 5 * 5).
The result is 125.

2. Exponentiation with Negative Exponent

You can use negative numbers as exponents to find the reciprocal of the base raised to the positive exponent.

let base = 4;
let exponent = -2;
let result = base ** exponent;

console.log(result); // Output: 0.0625

Explanation

4 ** -2 is the same as 1 / (4 ** 2), which equals 1 / 16 or 0.0625.

3. Exponentiation with Fractional Exponent

Fractional exponents can be used to find roots of numbers. For example, raising a number to the power of 0.5 is the same as finding the square root.

let base = 16;
let exponent = 0.5;
let result = base ** exponent;

console.log(result); // Output: 4

Explanation

16 ** 0.5 is the same as finding the square root of 16, which equals 4.

4. Exponentiation with Zero Exponent

Any non-zero number raised to the power of 0 is 1.

let base1 = 10;
let base2 = -5;

console.log(base1 ** 0); // Output: 1
console.log(base2 ** 0); // Output: 1

Explanation

10 ** 0 and (-5) ** 0 both result in 1 because any number raised to the power of 0 equals 1.

5. Chaining Exponentiation

You can chain exponentiation operations, but be careful with the order of operations (right-associative).

let result = 2 ** 3 ** 2;

console.log(result); // Output: 512

Explanation

The exponentiation operator is right-associative, so 2 ** 3 ** 2 is evaluated as 2 ** (3 ** 2).
3 ** 2 is 9, so the expression becomes 2 ** 9, which equals 512.

6. Using Exponentiation in Compound Expressions

You can use the exponentiation operator in larger expressions or combine it with other operators.

let x = 3;
let y = 2;
let result = 5 + x ** y * 2;

console.log(result); // Output: 23

Explanation

The expression 5 + x ** y * 2 is evaluated as 5 + (3 ** 2) * 2.
3 ** 2 is 9, so the expression becomes 5 + 9 * 2.
9 * 2 is 18, and 5 + 18 is 23.

7. Exponentiation Assignment Operator (**=)

The exponentiation operator also has an assignment variant, **=, which raises the value of a variable to a specified power and reassigns it to the variable.

let number = 4;
number **= 3; // Equivalent to: number = number ** 3;

console.log(number); // Output: 64

Explanation

number **= 3 is shorthand for number = number ** 3.
Here, 4 ** 3 equals 64, so number is updated to 64.

Summary

The exponentiation operator (**) in JavaScript is a concise and powerful way to raise a number to a specific power. Here’s a quick recap of its usage:

By mastering the exponentiation operator, you can easily handle complex mathematical computations and make your code more readable.

It is a cleaner alternative to using Math.pow() and supports various numerical operations such as roots, powers, and scientific calculations.