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Exponentiation Operator in JavaScript

samanthaming profile image Samantha Ming ・2 min read

Code Tidbit by SamanthaMing.com

I always found the old way of writing an exponentiation expression a bit awkward. Luckily, the exponentiation operator was introduced. This syntax also makes it more similar to other languages (ie. Ruby, Python). Cool πŸ‘

// Old way
const old = Math.pow(3, 7);
// 2187

// βœ… ES7 way 
const es7 = 3 ** 7;
// 2187

Infix Notation

The use of ** is called infix notation. It is characterized by the placement of operators between operands. Other popular infix notations include: + or -.

The reason this syntax was introduced is because:

Infix notation is more succinct than function notation, which makes it more preferable

Exponentiation in Other Languages

Also, you will notice this syntax is very similar to other languages:

// Python
a ** b

// Ruby
a ** b

// Perl
a ** b

// F#
a ** b

I actually like that it's similar to other languages. Because it makes picking up JavaScript a lot of easier for those folks and they can be up and running very quickly.

Assignment Operator

You must have seen arithmetic operator combined with the assignment operator. For example +=:

a += b

// Same as
// a = a + b

Well, similarly, this can also be done with the exponentiation operator. **=:

a **= b

// Same as
// a = a ** b

Negative Base

There's one bit of a gotcha. When you have a negative base, you will have to wrap it around parenthesis.

// ❌ Syntax Error
const wrong = -3 ** 7;

// βœ…
const correct = (-3) ** 7;

However, this isn't an issue if you use the older function way.

const works = Math.pow(-3, 7);

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